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JOURNAL 

OF THE 

AMERICAN SOCIETY 
OF AGRONOMY 



VOLUME 13 



1921 



PUBLISHED BY THE SOCIETY 



PRESS OF 
THE NEW ERA PRINTING COMPANY 
LANCASTER, PA. 



DATES OF ISSUE. 



Pages 1-48, January 15, 1921. 
Pages 48-88, February 15, 1921. 
Pages 89-136, March 15, 192 1. 
Pages 137-184, April 30, 1921. 
Pages 185-232, September 25, 192 1. 
Pages 233-288, October 15, 192 1. 
Pages 289-336, January 10, 1922. 
Pages 337-382, January 28, 1922. 



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CONTENTS. 
No. i. JANUARY. 

Pagb. 

Newton, R. — The Quality of Silage Produced in Barrels i 

Ellett, W. B., and Wolfe, T. K.— The Relation of Fertilizers to Hessian 

Fly Injury and Winterkilling in Wheat 12 

McRostie, G. P. — Inheritance of Disease Resistance in the Common Bean 15 
Swanson. C. O. — Hydrocyanic Acid in Sudan Grass and Its Effect on 

Cattle 33 

Hartwell, Burt L., and Damon, S. C. — Six Years' Experience in Im- 
proving a Light, Unproductive Soil 37 

Garber, R. J. — A Preliminary Note on the Inheritance of Rust Resistance 

in Oats (Fig. 1) 41 

Agronomic Affairs. 

The Society in 192 1 43 

Book Review (Harris' Soil Alkali) 44 

Membership Changes 46 

Notes and News 46 

International Crop Improvement Association 48 

No. 2. FEBRUARY. 

Call, L. E. — Prerequisites in Agronomy Subjects 49 

Wentz, John B. — The Standardization of Courses in Field Crops 53 

Slate, William L., Jr. — The First College Course in Field Crops 59 

Stevenson, W. H., and Brown, P. E. — The Teaching of Soils in Agricul- 
tural Colleges 63 

Miller, M. F. — The Teaching of Soils 71 

Beaumont, A. B. — The Introductory Course in Soils 79 

Cox, J. F. — The Michigan Plan for Distributing Improved Crop Varieties 82 
Agronomic Affairs. 

The Symposium on Agronomic Teaching 85 

Membership Changes 85 

The Chicago Meeting 85 

Notes and News 86 

No, 3. MARCH. 

Piper, C. V. — The Symposium on Liming 89 

True, Rodney H. — The Function of Calcium in the Nutrition of Seedlings 91 
Hartwell, Burt L. — Need for Lime as Indicated by Relative Toxicity of 

Acid Soil Conditions to Different Crops 108 

Conner, S. D. — Liming in Its Relations to Injurious Inorganic Compounds 

in the Soil (Fig. 2) «3 

537046 



vi 



CONTENTS. 



Lyon, T. L. — The Effect of Liming on the Composition of the Drainage 



Water of Soils 124 

Agronomic Affairs. 

Back Numbers of the Journal 131 

Membership Changes 131 

Notes and News 132 

Meeting of the New England Section 133 

Association of Southern Agricultural Workers 134 

Western Canadian Society of Agronomy 135 

No. 4. APRIL. 

MacIntirf., W. H. — The Nature of Soil Acidity with Regard to Its Quan- 
titative Determination 137 

Plummer, J. K. — The Effects of Liming on the Availability of Soil Potas- 
sium, Phosphorus, and Sulfur 162 

Fri ar. William. — The Fineness of Lime and Limestone Applications as 

Related to Crop Production (Fig. 3) 171 

Agronomic Affairs. 

Membership Changes 184 



No. 5. MAY. 



bfoOEKS, C. A., and MalIntirk. W. H. — The Comparative Effects of Va- 
rious Forms of Lime on the Nitrogen Content of the Soil (Figs. 4-8) 185 
Li pM a n, Jacob G. — The Value of Liming in a Crop Rotation with and 

without Legumes 206 

GARDNER, FRANK D. — Liming as Related to Farm Practice 210 

Blair, A. W. — A Comparison of Magnesia!) and Nonmagnesian Limestones 220 
SVlLSON, B. 1).— Sulfur Supplied to the Soil in Rainwater 226 

Agronomic Affairs. 

Delay in May Issue 229 

Membership Changes 229 

B00V Review (Bennett's "The Soils and Agriculture of the Southern 

States") 229 

Notes and News 230 

1 "ii ptcim c of Western Agronomists 232 

Not. 6 7. SEPTEMBER OCTOBKR. 

SCOTT, Hllfl UL, Tin Influence of W heat Straw on the Accumulation of 

Nitrates in the Soil (Figs. 16) 233 

\V nkahayaski, S.— A Study of Hybrid Oats, Avena slerilis X Avcna 

orientals 259 

\ 1 n am., If. N.— A Study of the Literature Concerning Poisoning of Cattle 

hy (he PrtJ i< \< id 111 Sorghum, Sudan Crass, and Johnson Grass 267 

Sih ii' • I us B. — CroM-Pollination of Milo in Adjoining Mows 280 



CONTENTS. vii 

Agronomic Affairs. 

Annual Meeting- of the Society 282 

Book Review (Thatcher's "The Chemistry of Plant Life") 283 

Notes and News 285 

Conference on Farm Crops Teaching 288 

No. 8. NOVEMBER. 

Arny. A. C, and McGinnis. F. W. — Methods of Applying Inoculated Soil 

to the Seed of Leguminous Crops 289 

Spillman, W. J. — A Plan for the Conduct of Fertilizer Experiments 304 

Vaile, R. S. — The Interpretation of Water-Requirement Data 311 

Harris, F. S. — Comment on R. S. Vaile's Discussion of Utah Results 316 

Stewart, George. — Varietal Nomenclature of Oats and Wheat 318 

Brown, Percy Edgar. — The Teaching of Soil Bacteriology 323 

Kirkpatrick, Roy T. — The Approved Seed Plan of the Missouri Corn 

Growers' Association : 330 

' DunlavY, Henry. — Frequency and Importance of Five-Lock Bolls in 

Cotton 332 

Wiggans. R. S. — Home-Grown and Imported Red Clover Seed 334 

Agronomic Affairs. 

Toronto Meeting of the Society 335 

Membership Changes 335 

Notes and News 336 

No. 9. DECEMBER. 

Mooers C. A. — The Agronomic Placement of Varieties (Figs. 17-27) 

(Presidential Address) 337 

Hartwell, Burt L. — Relative Growth Response of Crops to Each Fertilizer 
Ingredient and the Use of This Response in Adapting a Fertilizer 

Analysis to a Crop 353 

Agronomic Affairs. 

Minutes of the Annual Meeting 359 

Report of Committee on Standardization of Field Experiments 368 

Report of Committee on Terminology 374 

Report on Advisory Board to the National Research Council 375 

Report of t^e Editor 3/6 

Notes and News •• 37^ 

Index 380 



JOURNAL 

OF THE 

American Society of Agronomy 

Vol. 13. January, 1921. Xo. 1 



THE QUALITY OF SILAGE PRODUCED IN BARRELS. 1 

R. Xewtox.- 

The increasing popularity of the silo, even in sections where corn 
growing is not profitable, has led to considerable experimentation to 
determine the suitability for silage purposes of various other crops. 
One of the first problems in this work is to secure satisfactory con- 
tainers. Formerly it was supposed by many that these must be large 
enough to insure the high temperature thought to be necessary for 
proper fermentation. But the impression that high temperatures pre- 
vailed in large silcs was apparently based on observations near the 
surface, or in silos poorly filled or poorly constructed, where fermen- 
tation would be accelerated by the access of air. Lamb (8) 3 observed 
temperatures as high as 130° F. at or near the surface of the silage, 
while deep in the silo they rarely exceeded 8o° F. Xeidig (9) tabu- 
lates the temperatures in three large silos for the first three weeks 
after filling. These varied from 76° F. to 91 F. at the center, and 
47 to 76 at the wall. In all three silos the silage was pronounced 
excellent, and the fermentation temperatures assumed to be normal. 
Other experimenters have demonstrated that silage equal in quality 
to that in large silos, as indicated by appearance and chemical compo- 
sition, can be produced in containers at least as small as one quart, at 
ordinary laboratory temperatures. 

1 Contribution from the Department of Field Husbandry, University of Al- 
berta, Edmonton South, Alberta. Received for publication August 3, 1920. 

2 Assistant professor of field husbandry. University of Alberta. Acknowl- 
edgment is due to Dr. A. L. F. Lehmann, head of the Department of Chem- 
istry, for providing facilities for the analytical work, and to Prof. A. A. 
Dowell, head of the Department of Animal Husbandry, for cooperation in 
the palatability test. 

3 Numbers refer to "Literature cited." p. n. 

1 



2 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

The work of Swahson and Tague (14) indicates that the relatively 
heavy pressure obtaining in most parts of large silos is of importance 
only in that it makes exclusion of air more certain. Using quart milk 
bottles as containers for alfalfa silage, with four degrees of tightness 
of pack (full, three fourths, one half, and one fourth pack) they 
found little difference in the percentage of chemical change produced. 

A suitable container for experiments with a large number of crops 
and combinations of crops must be cheaply and easily obtained, rela- 
tively small in size, yet large enough to contain sufficient silage for at 
least simple palatability tests. A preliminary experiment to determine 
the -nitability of barrels for this purpose was undertaken by the De- 
partment of Field Husbandry at the University of Alberta in the fall 
of [919. At that time it was not known that these had been tested by 
other experimenters. During the suceeding winter Westover and 
( rarver ( 16) published an account of their experiment with barrels at 
Redheld. S. Dak., in 1919, and noted the use of the same containers 
by the Illinois station in 1889. 

DESCRIPTION OF THE EXPERIMENT. 

Four oil barrels, which had been in use as water barrels, and one 
-mailer barrel were filled respectively with the following crops: (a) 
Northwestern Dent corn, in the early milk stage of maturity ; (b) 
Mammoth Russian sunflowers, with seeds just beginning to develop; 

I equal parts of the foregoing varieties of corn and sunflowers; (d) 
Banner oats, in the dough stage; (c) Silverhull buckwheat, with seeds 
well developed, some almost mature. All of these crops were frozen 
September! 1. The corn and sunflowers were cut September 3, the 
oats and buckwheat September 5. 

The barrels were taken to the field, together with a small hand feed 
c utter and field scales, and filled and weighed as the crops were being 
-:< d. 'flu- material was cut into lengths of about a half inch and 
firmly packed, being tamped down with a small fence post. The 
barrels held about 250 pounds each of the silage. Some water was 
added to the corn, which had wilted rapidly after freezing, but the 
subsequent analysis showed this to have been unnecessary. After 
filling. loose fitting cover- were placed on the barrels, and they were 
Itored in the basement of the experimental barn, where they remained 
all winter. It wa- intended that the covers should he weighted but, 
to an oversight, this was not done. They were removed from 
Storage June J, I'/Jo. opened one per day, and, after sampling for 
chemical examination, the best portion used for a palatability test. 



NEWTON : SILAGE PRODUCED IN BARRELS. 



3 



METHOD OF SAMPLING. 

The gross weight of barrel and silage was first recorded. The 
blackened portion from the top was then discarded, together with an 
additional quantity containing mold or other evidence of decay, until 
fair quality silage, of good odor and free from mold (except in very 
small patches or around the edge) was reached. After reweighing 
the barrel, a further quantity, called portion A, was removed, until, 
judging by appearance and odor, it was considered that first quality 
silage had been reached. Portion A was thoroly mixed on a clean 
cement floor, sampled by repeated quartering, then discarded. After 
another weighing, the remainder, called portion B, consisting of first 
quality silage, was emptied on the floor and sampled. The samples of 
800 to 1,000 grams each from portions A and B were packed into 
clean quart sealers and taken to the chemical laboratory for imme- 
diate examination. After sampling, portion B was shoveled back into 
the barrel and taken to the dairy stable for a palatability test. Altho 
portion A was discarded as second quality silage, in all cases it was 
pronounced by stock men to be quite fit for use. The weights and 
percentages of the different portions shown in Table 1 give some in- 
dication of the general quality of the silage in the different barrels. 

Table i. — Weights and percentages of different portions of silage from barrels. 



Kind of silage. 


Total 
silage. 


Spoiled 
silage 


Portion 
A. 


Portion 
B. 


Spoiled 
silage. 


Portion 
A. 


Portion 

B. 




Pounds. 


Pounds. 


Pounds. 


Pounds. 


Per cent. 


Per cent. 


Per cent. 


Corn 


330 


"107 


65 


158 


26.9 


21.3 


5i-8 


Sunflowers 


259 


93 


70 


96 


35-9 


27.0 


37-i 


Corn and sunflowers . . . 


226 


80 


5i 


95 


35-4 


22.6 


42.0 


Oats 


223 


32 


52 


139 


14.4 


23-3 


62.3 


Buckwheat 


186 


a po 


19 


77 


45-5 


10.8 


43-7 



a The weights of spoiled silage include 25 pounds excess juice in the case of 
the corn, and 10 pounds in the case of the buckwheat. These quantities are 



subtracted before calculating the percentages. 

The original weights of the silage material are not recorded as, in 
proportion to the size of the barrels, the amount of spoilage by ex- 
posure to the air at the top is so large they are not considered to be of 
value. An improvement could be effected by interposing a screen a 
short distance from the top when filling, as used by Eckles, Oshel, and 
Magruder (5), to separate the spoiled material from the rest. It 
would then be possible to estimate the loss by fermentation. 

APPEARANCE OF SILAGE IN BARRELS WHEN OPENED. 

The silage in all the barrels had settled to a certain extent, the oats 
3 inches from the top of the barrel ; corn and buckwheat, each 5 



4 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



inches ; sunflowers and corn and sunflowers, each I foot. The two 
last had also settled somewhat away from the sides of the upper part 
of the barrels, thus increasing the spoilage by admitting air, mold 
being found around the edges as far down as the center of the bulge. 
The depth of blackened material on top was about 3 inches in the 
buckwheat. 4 inches in the oats, and 5 inches in the corn and sun- 
flowers, singly and mixed. A further depth of about 2 inches in the 
oats. 3 inches in the corn and sunflowers, and 9 inches in the buck- 
wheat were removed before silage fit for use was reached. By turn- 
ing the barrels on their sides, about 25 pounds of excess juice w r ere 
drained out of the corn, 10 pounds out of the buckwheat, and an un- 
appreciable amount out of the sunflowers. Tho the buckwheat silage 
contained excess moisture, the upper portion had dried out somewhat, 
probably clue to insufficient pressure, thus accounting for the moldy 
condition which made it necessary to discard a greater depth than in 
the other barrels. The barrel of corn and sunflowers mixed had 
leaked around the bottom, and small patches of mold were found 
thruout the whole of its contents, tho not enough to materially affect 
its suitability for feeding. An insignificant amount of mold was also 
found around the edge of the oats, even in the bottom half of the 
barrel. Both portions A and B in all barrels had the characteristic 
silage odor, more pronounced and pleasant in portion B. The buck- 
wheat silage had a particularly attractive odor, being pronounced, by 
the various persons to whom the samples were shown, as the most 
pleasant of the lot. 

PALAT ABILITY TEST. 

Portion B of each barrel was taken to the dairy stable for a pal- 
atability test, which was made on the evening of the day on which the 
barrel was opened. When the dairy herd of 10 cows had received 

their regular evening ration of 15 to 20 pounds each of peas and oats 
ilage, an additional 8 to 10 pounds each of experimental silage was 

[)la ed alongside j| in the manger. 

I he animal- showed no marked preference between the peas and 
0atfl Silage from the farm silo and the corn silage from the barrel. 
Tho all switched to the corn at first, all but two returned shortly to 
their regular feed, and later cleaned Up both impartially. 

All animals preferred their regular feed to the sunflower silage. 

• • ■ miffing at it the) left it to be eaten last. Some did not finish it 
•it once, and a few refused altogether the coarser pieces of stalk, which 
had to Ix el ancd out in the morning. It should be noted, however, 
that this herd had never previously been fed sunflower silage, so that 
usage may have been a factor. 



NEWTON I SILAGE PRODUCED IN BARRELS. 



5 



The corn and sunflowers mixed appeared about midway between 
the previous two in point of palatability. 

The oat silage was cleaned up with the greatest avidity by all ani- 
mals before they returned to their regular feed. 

The buckwheat silage was just a little more relished than sun- 
flowers, but inferior to the others. It was left to be eaten last, but 
finished without waste by all stock. 

CHEMICAL ESTIMATION OF QUALITY IN SILAGE. 

Moisture Content. — In the production of good silage, a moisture 
content sufficient to make conditions favorable for active fermentation 
is necessary. It is generally held, however, that an excessive amount 
of moisture is injurious. The so-called "sour" silage, resulting from 
the ensiling of very immature corn, is attributed largely to the high 
moisture content of the corn, tho differences in sugar content at dif- 
ferent stages of growth must also affect the amounts of acid produced. 

Swanson and Tague (14), in a study of alfalfa silage, preserved 
alone and with various supplements, found that the amount of mois- 
ture present may be a favorable condition for the development of the 
proper amount of acidity, but is not by itself a determining factor. A 
high moisture content or a low moisture content did not necessarily 
correspond with a proportional development of acidity. In their table 
of chemical analyses, samples grading 100 percent for quality are 
found between the two extremes of 58.01 percent and 79-9° percent 
moisture. 

Xeidig (10) selected 75 percent as the optimum moisture content 
and, in filling experimental silos with various grasses and legumes, 
added water when necessary to raise the percentage to that figure. 

After seventeen trials of legumes for silage, over a period of four 
years, Eckles (4) concluded that the wide variation in results with 
these crops, as reported in agricultural literature, is largely explained 
on the basis of the dry-matter content of the materials used. He 
states that a dry-matter content of approximately 40 percent gives the 
best results, and that when it is as low as 20 to 25 percent the silage 
will have an extremely disagreeable odor and be almost worthless for 
feeding purposes. With Sudan grass, however, no special attention 
to dry matter content was necessary, the sugar content at any stage of 
growth being sufficient to insure a suitable fermentation. 

Henry and Morrison (6) give the following average percentages of 
moisture content for different kinds of silage: Well matured corn, 
73.7; immature corn, 79.0; oats, 71.7; peas and oats, 72.5; sugar beet 
pulp, 90.0. 



6 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Acidity. — It has long been known that the development of acid is 
an important phase of silage fermentation. The acid content is now 
recognized as an important index of quality. It is produced almost 
entirely in the first two or three weeks, and acts as a preservative, pre- 
venting further material changes as long as air is excluded. 

Samarani (13) found, at a fermentation temperature of 104 F. 
to 140° F.. the average acid content to consist of 70 percent acetic acid 
and up to 20 percent lactic acid. When pressure was applied, how- 
ever, driving out the oxygen and lowering the temperature, the pro- 
portions of lactic and acetic acids were reversed. Similarly, Bechdel 
( 1 ) noted the ratio of acetic acid to lactic acid to be greater in silage 
taken from along the silo walls than in that taken from points away 
from the walls. This he explained by assuming that the silage does 
not pack as firmly along the walls as at other places in the silo. It 
would appear, therefore, that the kind of acid present is an important 
indication of the character of the fermentation which has taken place, 
whether essentially preservative or unduly destructive. 

Dox and Neidig (2), after studying the volatile acids of silage from 
different types of silos, reported that acetic acid comprised about 90 
nt of all the volatile acid present. The remainder consisted 
chiefly of propionic acid. Small amounts of butyric and valeric acids 
w ere present in sonic samples, the butyric in considerable quantity in 
spoiled silage. In a later publication (3) reporting a further study 
of the nonvolatile acid, they concluded that lactic acid is normally 
present in silage in excess of the volatile acids. The average ratio 
they found to be 1.0 to 0.75. 

Reed and Fitch ( 12) found as much acid in alfalfa silage as in kafir 
or cane silage, tho the alfalfa silage was inferior. They took this to 
indicate that the acid content is not always an index of quality. But 
Neidig (10), in determining the acidity of silage made from various 
• ropS, found no more than a trace of lactic acid present in any sample 
of alfalfa milage he examined, while butyric acid developed as the 
silage became older, lie is of the opinion that 

The crin-rion of good silage is the- kinds of acid present rather than the 
quantity. Good silage must have a sufficient quantity to insure its keeping, 
but beyond this point silage may vary in amount of acidity and yet he classed 
a< normal silage. 

Amtno mitogen. — The amount of amino nitrogen present in silage 
may give further evidence of the character of its fermentation. A 
large proportion Of the total nitrogen being found in this form would 
■ eXO live protein decomposition, which is wasteful and in- 
jurious tO the palatability of the silage. 



NEWTON : SILAGE PRODUCED IN BARRELS. 



7 



Swanson and Tague (14) reported about one third of the nitrogen 
in good alfalfa silage and as much as half in bad alfalfa silage in 
amino form. They made the determinations of amino nitrogen by 
the formol-titration method and found a comparison of the titration 
figures for acidity and amino nitrogen to give an indication of quality. 
In good silage the figure for acidity was always larger than the figure 
for amino nitrogen, the difference being greatest in the best silage. 

That the amount of amino nitrogen varies with the crop used is in- 
dicated in a later paper by the same authors (15). They found it to 
be notably less in sweet clover silage than in alfalfa silage. Huntei 
(7) demonstrated the protein-sparing effect of carbohydrate supple- 
ments to alfalfa silage. When an available carbohydrate was added, 
the acid content was increased and the amino nitrogen decreased. In 
view of this evidence and the fact that in general the presence of acid 
tends to inhibit proteolytic fermentation, excessive protein decompo- 
sition in crops or mixtures containing a sufficient supply of utilizable 
carbohydrates would not be expected. The existence of a large pro- 
portion of the nitrogen in amino form would suggest that the acid 
content had been destroyed by molds, due to incomplete exclusion 
of air. 

CHEMICAL EXAMINATION OF SAMPLES. 

The samples of portions A and B, taken when the barrels were 
opened, were analyzed the same day for moisture, total acidity, vola- 
tile acidity, and amino nitrogen. The total nitrogen was determined 
later, using the residues from the moisture determinations. Samples 
from the farm silo were analyzed for comparison. This silo had been 
filled with alternate layers of corn and a mixture of peas and oats, a 
few loads, varying in number, in each layer. 

Moisture Content. — Duplicate samples of 100 grams of silage were 
dried to approximately constant weight in an electric oven at ioo° to 

103 c. 

Preparation of Water Extract. — Water extracts were made by 
placing 100-gram samples in quart jars, with 425 c.c. distilled water. 
All distilled water used for extractions and dilutions thruout the work 
was freshly boiled to free it from carbon dioxid. The jars were 
shaken in a shaking machine 2}/ 2 hours and the contents filtered. A 
portion of 25 c.c. extract was approximately equal to 5 grams of 
silage, but necessary corrections were made later from the figures ob- 
tained in the moisture determinations. A comparison of buckwheat 
silage juice, as drained out of the barrel, with water extract prepared 
as above, on the basis of an equivalent quantity of silage, showed 



8 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



practically the same amounts of acid and amino nitrogen in each. The 
necessity of completing the determinations on the water extract at 
once was proved by the fact that the following morning the portion 
remaining in the laboratory was invariably covered with a scum. 
When it was desired to make further studies of the extract, it was 
sterilized without appreciable loss by boiling gently under an inverted 
condenser. 

Total Acidity. — Duplicate portions of 25 c.c. extract were pipetted 
into 500 c.c. erlenmeyers, diluted with 200 c.c. water, and titrated with 
.05 normal sodium hydroxid, using phenolphthalein as an indicator. 

VolatUe Acidity. — A portion of 100 c.c. extract was measured into 
a 500 c.c. distilling flask, the graduate then being washed with 20 c.c. 
water from a pipette and the washings added to the contents of the 
flask. The dimensions of the distilling apparatus and the time of dis- 
tillation were kept uniform thruout, 80 c.c. of distillate being collected 
in about 30 minutes. The residue and distillate were both made up to 
100 c.c. and duplicate portions of 25 c.c. titrated. The slight loss 
which usually occurred in distillation was added to the volatile acid. 
The total amount of volatile acid was calculated from Duclaux' con- 
stants as published by Dox and Neidig (2). For this purpose it was 
assumed that the volatile acid was 90 percent acetic and 10 percent 
propionic. 

The above method of determining volatile acidity, while probably 
not as exact as steam distillation under reduced pressure, is much 
more quickly done, and was considered sufficiently accurate for the 
purpose of estimating the quality of silage. The slight volatility of 

tic acid at 100 C. would hardly lead to appreciable error. Dox 
and Xeidig 1 2 ) quote Jensen as authority for the statement that 5 
• ra tit of the lac-tic acid passes Dvet with the distillate when a dilute 
solution i- redn cd to one eleventh of its original volume. The boil- 
in;' point of tlx silage extracts at the latter concentration was experi- 
mentally determined to be about 1 i8° C, whereas it increased com- 
paratively little up to the point to which the distillations were carried 
in tlx- present Mudv. The initial boiling point was about 98.5 C. at 
this altitude. It readied 100 ( '. when about 65 c.c. had passed over, 
and [03.5 ( . when So c.c. (the amounl used) had been collected. 
P.evond this point it increased rapidly. 

Amino Xitmycn. The amino nitrogen was determined by titration, 
iisintf this method ftl described by Plininier (ll), with small niodi- 
r>ns 'lh«- same portions of extracl which had been titrated for 
•-••a! a<id:t\ were u-ed at once for this determination. After adding 
of dilute neutral formaldehyde, the portions were .allowed to 



NEW TON : SILAGE PRODUCED IN BARRELS. 



stand 15 minutes, and then retitrated with .05 normal sodium hy- 
droxide. 

Total Nitrogen. — The total nitrogen was determined by the official 
Kjeldahl method, using the residues from the moisture determinations. 

The results of the chemical examination of the samples are given 
in Table 2. For comparison, an estimate of the quality of the sam- 
ples, as judged by appearance and odor at time of sampling, is in- 
cluded. 

DISCUSSION OF TABLE 2. 

The moisture content of the corn and sunflowers, both singly and 
mixed, was very high, but did not appear to exercise a detrimental 
effect. It did not correspond to a proportional development of acidity. 
In fact, the acidity of portion B of each barrel was greater than that 
of portion A, tho the latter in every case contained more moisture. 

The percentage of total acid is expressed on the basis of silage 
(column 4) and dry matter (column 12), as some of the authors cited 
use the latter method. In the poorer samples the total acidity was 
proportional to the quality as judged by appearance and odor at the 
time of sampling, but among the good samples there was considerable 
variation. As already noted, however, taking each barrel individually, 
the total acidity was greater in portion B, the better part of the barrel. 
The samples from the farm silo had a much greater acidity than the 
others on- the basis of silage, but not on the dry matter basis. They 
did not appear to be superior in any respect to similar material from 
the barrels. 

The ratio of nonvolatile to volatile acidity was largest in the best 
samples and smallest in the poorest. In all samples the quality as 
judged by this ratio agreed very closely with the estimate at sampling. 

The total acidity is repeated in column 8, placed beside the column 
for amino nitrogen, both expressed as cubic centimeters .05 normal 
in 5 grams silage, to facilitate the comparison suggested bv Swanson 
and Tague (14). In all cases the figures for acidity are much larger 
than those for amino nitrogen, the difference being greatest in the 
best samples. 

The ratio of amino nitrogen to total nitrogen, however, did not 
vary as might have been expected from the foregoing estimates of 
the quality of the samples. The proportion of amino nitrogen tended 
rather to increase in the better silage. The cause of this was not in- 
vestigated, but it should be remembered that the authors just cited 
worked with alfalfa as silage material, while the materials used in 
this experiment were relatively very poor in nitrogen, as shown by 
the last column of the table. 



10 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 2. 


—Chemical analysis 


of silage 


stored in 


barrels. 




Sample. 


Quality as 
judged by 
appearance 
and odor. 


Moisture. 


Total acid. 


Nonvolatile 

acid as 
lactic. 


Volatile 
acid as 
acetic. 


Ratio of 
nonvo'atile 
to volatile 
acid. 




Per cent. 


Per cent. 


Per cent. 


Per cent. 


Per cent. 




Corn: 














A 


90 
100 


88.30 
86.65 


1-4*3 
1.803 


0- 999 

1- 359 


0.414 
•444 


I : O.41 
I : 0.33 


B 




Sunflowers: 














A 


80 


85-55 
83.70 


1.029 
1-347 


.621 


.408 
•438 


1 : 0.66 


B 


100 


.909 


1 : 0.48 


Corn and sunflowers: 


A 


50 


85-45 


.141 


•045 


.096 


1 : 2.13 




B 


95 


83.65 


1. 182 


•756 


.426 


1 : 0.56 


Oats: 


A 


90 
100 


70.85 
70.40 


•729 
1.284 


•513 
.882 


.216 


1 : 0.42 
1 : 0.46 


B 


.402 


Buckwheat : 


A 


70 


77-90 


.666 


.306 


.360 


1 : 1. 18 


B 


100 


78.80 
95-90 


.786 
•705 


.522 
•459 


.264 
.246 


1 : . 5 1 
1 : 0.54 


Juice" 






r di in r»iiu . 














Corn 


100 


75-45 


2.718 


1.872 


.846 


i : 0.45 




Peas and oats 


100 


67.10 


2. 118 


1.404 


.714 


1 : 0.51 




Total 


Amino 


Total 


Ratio of 


Total acid 


Total nitro- 


Sample. 


acidity in 


nitrogen in 


nitrogen in 


amino to 


per 100 


5 grams 


5 grams 


5 grams 


total 


grams dry 


gen in dry 




silage. 


silage. 


silage. 


nitrogen. 


matter. 


matter. 




C c. 2 V 


C.c. s \j N. 


C.c. oV -W- 




Grams. 


Per cent. 


Corn: 














18.0 


2.0 


10.9 


1 : 5-45 


12.08 


i-3i 




B 


22.5 


3-6 


12.6 


1 : 3-50 


I3-5I 


1.32 




Sunflowers: 
















13-7 


1.2 


14.9 


1 : 12.42 


7.12 


1.44 




B 


17.4 


1.9 


13-4 


1 : 7-05 


8.26 


LIS 




Corn and sunflowers: 














A 


2.1 


0.8 


17-3 


1 : 21.63 


•99 


I.67 




B 


15-5 


2.1 


15-5 


1 : 7-38 


7-23 


i-33 


Oats: 














A 


1 
9-3 


0.7 


30.6 


1 : 4-57 


2.50 


1.47 


B 


16.5 


9-3 


31-7 


1 : 3-4i 


4-34 


1.50 


Buckwheat : 














A 


94 


3-7 


31.7 


I : 8.57 


3.01 


2.01 




B 


I0.2 


4.2 


30.6 


1 : 7.29 


3-71 


2.02 




Juice" 


9-2 


3 '7' 




















Farm lUo< 














Corn 


34-9 


10.4 


37-7 


1 : 3-63 


11.07 


2.15 






27-5 


8.8 


32.0 


1 : 3.64 


6.44 


1-36 





1 Figures, except for moisture, are calculated for equivalent quantities of 

silage. 



SUMMARY. 

Jli' result! of thil preliminary experiment indicate that barrels arc 
qtUte Ittlt&blc n « xpcrimental containers for silage. The quality of 
the nlage produced was judged by appearance, odor, palatabilit v, and 
the various chemical tests sn^estcd by the literature on the subject. 



NEWTON : SILAGE PRODUCED IN BARRELS. 



I 1 



In comparison with published results of similar tests and with samples 
taken at the same time from an ordinary farm silo, the material from 
the barrels was considered to be in all important respects normal 
silage. 

LITERATURE CITED. 

I. Bechdel, S. I. Studies in the preservation of corn silage. In Pa. Agr. 
Expt. Sta. Ann. Rpt. 1915/16, pp. 323-348. 1917. 

2 Dox, A. W., and Neidig, R. E. The volatile aliphatic acids of corn silage. 

Iowa Agr. Expt. Sta. Research Bui. 7. 1912. 

3 . Lactic acid in corn silage. Iowa Agr. Expt. Sta. Research Bui. 10. 

I9I3- 

4. Eckles, C. H. Legumes, Sudan grass and cereal crops for silage. Mo. 

Agr. Expt. Sta. Bui. 162. 1919. 

5. , Oshel, O. I., and Magruder, D. M. Silage investigations: Normal 

temperatures and some factors influencing the quality of silage. Mo. 
Agr. Expt. Sta. Research Bui. 22. 1916. 

6. Henry, W. A., and Morrison, F. B. Feeds and Feeding, 16th ed. Au- 

thors, Madison, Wis. 1916. 

7. Hunter, O. W. Bacteriological studies on alfalfa silage. In Jour. Agr. 

Research, v. 15, no. 11, p. 571-592. 1918. 

8. Lamb, A. R. The relative influence of microorganisms and plant enzyms 

on corn silage fermentation. Iowa Agr. Expt. Sta. Research Bui. 40. 
1917. 

9. Xeidig, R. E. Chemical changes during silage formation. Iowa Agr. Expt. 

Sta. Research Bui. 16. 1914. 

10. . Acidity of silage made from various crops. In Jour. Agr. Research, 

v. 14, no. 10, p. 395-409. 1918. 

11. Plimmer, R. H. A. Practical Organic and Bio-chemistry, revised ed. Long- 

mans, Green and Co., London. 1918. 

12. Reed, O. E., and Fitch, J. B. Alfalfa silage. Kans. Agr. Expt. Sta. Bui. 

217. 1917. 

13. Samarani, F. The preparation of ensilage. In Bollettino del Ministero 

di Agricultura, Industria e Commercio, year 13, nos. 8-12, p. 87-103. 
Rome, 1913. (Abs. in Bui. Foreign Agr. Intell., v. 5, no. 3, p. 206-207. 
Ottawa, 1915.) 

14. Swanson, C. O., and Tague, E. L. Chemical studies in making alfalfa 

silage. In Jour. Agr. Research, v. 10, no. 6, p. 275-292. 1917. 
15- • Chemistry of sweet clover silage in comparison with alfalfa silage. 

/;/ Jour. Agr. Research, v. 15, no. 2, p. 1 13-132. 1918. 
16. Westover, H. L., and Garver, S. A cheap and convenient experimental 

silo. In Jour. Amer. Soc. Agron., v. 12, no. 2, p. 69-72. 1920. 



12 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



THE RELATION OF FERTILIZERS TO HESSIAN FLY INJURY 
AND WINTERKILLING OF WHEAT. 1 

W. B. Ellett and T. K. Wolfe. 2 

The damage to wheat from Hessian fly injury and winterkilling in 
the southwestern portion of Virginia during the past season was un- 
usually severe. The early fall was dry, followed by damp, warm 
weather until about November I. As a result wheat, even when 
seeded at what was ordinarily the proper date, suffered heavily from 
attaeks of the Hessian fly. The winter temperature was compara- 
tively mild, but with frequent and rapid fluctuations, while the snow- 
fall was unusually light. As a consequence, much wheat winter- 
killed. 

In order to obtain data with regard to the winter injury and Hes- 
sian fly damage, notes were taken on some of the wheat experimental 
plats a; IUacksburg. The data presented in Table I were taken from 
plats which have been growing wheat continuously since 1908. The 
treatments shown have been made annually just previous to seeding 
the wheat, with the exception of the manure, which has been applied 
during the winter. The plats are one twentieth of an acre each. In 
making the counts on Hessian fly injury, the total number and the 
number of lodged -talks were counted in ten rows on each of the plats. 
All -talk- were not examined for the fly injury; only those stalks 
which had lodged at the time of counting were classed as injured by 
the fly. The counts were made just before the wheat matured. In 
addition to the count-. Table 1 also shows the yields from the various 
plats. The yields suggest the degree of winterkilling. 

Tin- data presented in Table 2 were obtained from a rotation experi- 
ment with fertilizers started in 1 <;0< ). The rotation consists of corn, 
• ■. and grass ;m( I clover two years. The treatments shown are 
made annually exiapt where noted otherwise in the table. During 
the first live years of the experiment the applications of commercial 
fertilizer! were half the amounts as now given. The applications of 
manure have been the same since the experiment was started. The 
decree of winterkilling is indicated by the yields. 

' ntributioti from the Virginia Agricultural Kxpcrimcnt Station, Hlacks- 
l»nrK. \ I ' fi\cfl »'.r publication August \j, M)jo. 

■ I in mist ami associate agronomist, respectively, at the Virginia Agricultural 
Kxpcrimcnt Station. 



ELLETT & WOLFE : FERTILIZERS OX WFIEAT. 



13 



In Table 1 data are presented in regard to Hessian fly injury and 
winterkilling of wheat grown under continuous cropping conditions. 



Table i. — The effect of fertilizers on Hessian fly injury and winterkilling of 

wheat. 



Plat 
No. 


Treatment. 


No. of 
Not lodged. 


stalks. 
Lodged. 


Percentage 
of stalks 
lodged. 


Yield of grain, 
bushels per 
acre. 


I 


Manure 10 tons, acid phosphate 












321 lbs 


4,096 


206 


4-79 


16.75 


2 


Acid phosphate 321 lbs 


1,308 


248 


15-94 


3.00 


3 


Manure 10 tons, floats 200 lbs., 












lime 1,200 lbs 


5.574 


728 


n-55 


24.83 


4 


Floats 200 lbs 


45i 


169 


27.26 


.92 


5 


Check 


356 


95 


21.06 


b 


6 


Manure 10 tons, floats 200 lbs 


3.636 


436 


10.71 


16.83 


7 


Manure 10 tons 


3.503 


417 


10.64 


14.17 


8 


Buckwheat turned under, floats 200 












lbs.° 








6 


9 


Check a 








6 


10 


Buckwheat turned under, floats 200 














839 


342 


28.96 


2.00 




Buckwheat turned under" 








b 


12 


Buckwheat turned under, acid phos- 












phate 321 lbs., lime 1,200 lbs 


2,016 


642 


24.15 


4-83 . 


13 


Check 


35i 


107 


23-36 


• 75 



" Xo counts made because of small number of plants. 
b No yield obtained because of small number of plants. 



It will be seen from Table 1 that when acid phosphate or manure 
has been used that the Hessian fly injury is smaller and the yield 
greater than when manure has not been used or when floats has been 
applied in place of acid phosphate. The fly injury ranges from 4.79 
percent in the manure-acid-phosphate plat to 28.96 percent in the 
buckwheat-floats-lime plat. The manure plat suffered 10.64 percent 
fly injury, which is next to the lowest. 

In Table 2 data are presented in regard to winterkilling as shown 
by yields secured from a rotation experiment with fertilizers in which 
corn, wheat, and grass were grown. 

Table 2— Effect of fertilizers on winterkilling of wheat as shown by yields. 

Grain, bushels Increase over 

Treatments. P er acre. check, bushels. 

Check 0.33 

438 lbs. acid phosphate 5-4° 5 °7 

Check 53 

308 lbs. dried blood, 438 lbs. acid phosphate, 200 lbs. 
muriate potash 9-53 9-0° 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Check 1.53 

43S lbs. acid phosphate. 200 lbs. muriate potash 8.60 7.07 

Check 1. 00 

308 lbs. dried blood. 200 lbs. muriate potash 1.33 .33 

Check 40 

30S lbs. dried blood. 438 lbs. acid phosphate 7.53 7.13 

Check 53 

16 tons manure once in four years before corn 18.40 17-87 

Check 3.20 

4 tons manure annually 18.33 I5- I 3 

Check 1. 00 

16 tons manure once in four years before corn, 438 
lbs acid phosphate annually 22.13 21.13 

Check 53 

218 lbs. floats 2.80 2.27 



It will be noted from Table 2 that manure has markedly prevented 
winterkilling, as shown by the yields. The results are also striking in 
that they indicate the element most needed to increase yield and de- 
crease the amount of winterkilling is phosphorus. In this regard 
acid phosphate lias been more satisfactory than floats. Under the 
conditions of this test it seems that phosphorus was the most impor- 
tant plant nutrient. 

Practically all the soils of Virginia are markedly deficient in phos- 
phoric and that plant nutrient must be supplied before material in- 
creases in yield can be secured. On many of the soils of the State 
the organic matter contenl 1- low and this in addition to phosphorus 
must be increased to secure larger crop yields. Thus it seems that 
phosphorus, unless supplied by commercial fertilizer, is nearly al- 
ways the limiting factor in crop production in Virginia, while often 
both phosphorus and organic matter limit crop yields. 

( M the materials used those which have increased crop yields and 
tied the Hessian fly injury and winterkilling i n Virginia to the 
grcatc extenl have been stable manure and acid phosphate. 



m rostie: disease resistance of beans. 



15 



INHERITANCE OF DISEASE RESISTANCE IN THE COMMON 

BEAN. 1 

G. P. McRostie. 2 

Scope of the Paper. 

The data and discussions recorded in this paper represent the re- 
sults of over three years' observations on the mode of inheritance in 
the common bean, Phaseolus vulgaris, of the factors concerned in the 
production of resistance to three common bean diseases of New York. 
The data were obtained mostly from material grown in connection 
with the New York bean investigations with which the writer was 
connected in the capacity of plant breeder. 

A short resume is included of the literature pertaining to the mode 
of inheritance of the factors responsible for disease resistance. No 
attempt has been made to include a complete bibliography of this 
subject, but enough data have been included to indicate the diversity of 
results that may be expected when working with different diseases. 

Previous Results on the Inheritance of Disease Resistance. 

The definite inheritance of disease resistance has been studied 
largely in late years and even yet the literature on the subject is de- 
cidedly limited. Biffen (3) 3 found that resistance to the yellow rust, 
Pitccinia glumarum Eriks. and Henn., in his cross between Rivet, a 
slightly susceptible wheat, and Red King, an extremely susceptible 
one, behaved as a recessive, all the F 1 plants and approximately 75 
percent of the F 2 plants having been susceptible. Nilsson-Ehle (7), 
in crosses between wheats resistant to yellow rust and varieties sus- 
ceptible to this disease, found susceptibility dominant in the F 1 and 
was of the opinion that a multiple-factor explanation of the genetic 
behavior of resistance was the correct one in his crosses. Vavilov 
(13), in crosses between Persian wheat, Triticum vidgare var. fuligi- 
nosum Al., which was immune to mildew, Erysiphe graminis D. C, 

1 Paper No. 81, Department of Plant Breeding, Cornell University, Ithaca, 
N. Y. Received for publication August 27, 1920. 

2 The writer wishes to acknowledge indebtedness for suggestion, assistance, 
and criticism to Dr. R. A. Emerson, Dr. D. Reddick, and Dr. M. F. Barrus. 
Appreciation is also expressed to Dr. W. H. Burkholder, who assisted with 
some of the inoculations and who also supplied a part of the cultures of the 
anthracnose fungus and all of those of the root-rot fungus. 

3 Reference is to " Literature cited," p. 32. 



1 6 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

and varieties of common bread wheats susceptible to this disease, se- 
cured Fj hybrids which were immune to the mildew. Stuckey (n), 
in breeding varieties of tomatoes resistant to blossom-end rot, found 
that resistance was transmitted as a dominant character. Tisdale 
{12), studying the inheritance of flax wilt, in crosses between resistant 
and susceptible flax varieties, obtained a great variety of results grad- 
ing all the way from F x generations that were wholly resistant to F x 
generations that were wholly susceptible. He attempts to explain his 
results on the basis of multiple factors, claiming that under normal 
conditions two or three factors in the homozygous condition would be 
enough to show apparent resistance. Under conditions exceptionally 
favorable for infection only those plants which had all factors con- 
cerned in the homozygous condition would show resistance. The 
gradation in the F a results might, therefore, be explained on the basis 
of severity of infection. 

Burkholder (4), in crosses between Wells' Red Kidney, a type of 
bean resistant to both 1 and (3 strains of Collctotr'chitm lindemuthi- 
anutn, and the White Marrow bean resistant to only the a strain (2), 
obtained in the F 2J out of a total of 473 plants tested, 362 which 
proved resistant and 111 which proved susceptible to this disease. 
These numbers show almost an exact 3 : 1 ratio and indicate a single 
factor difference between the resistant and susceptible plants with 
respect to the (3 strain of the anthracnose fungus concerned in the 
cross. McRostie (6)', in crosses between Wells' Red Kidney and the 
White Pea bean' resistant to the (3 strain of anthracnose, obtained a 
similar ratio. Out of a total of 1,970 second generation plants inocu- 
. 1.471 showed resistance and' 499 susceptibility to this disease. 

1 \\ KSTICATIONS. 

INHERITANCE OP RESISTANCE TO THE BEAN ANTHRACNOSE FUNGUS. 

The data included in this section are additional facts obtained since 
the publication of the author's first paper on this subject (6). A 
shod summary of this paper is given here to afford a better under- 
standing of the tables and discussions which follow. 

'I wo Itrains, 7 and fi. of the anthracnose fungus, Colletotrichitm 

tmdemutHionum (Sacc. and Magnl) Bri. and Cav;, are reported by 
Barrui (2), and the resistance and susceptibility to these strains of a 
large number of varities of beans is listed by him. The resistant 
parent Used in the CTOSSi s reported in the previous article was a strain 

of bean (Wells' Red Kidney) which was resistant to both strains of 
the fungus. The susceptible parent used was the Michigan Robust 



m'rostie: disease resistance of beans. 



17 



Pea bean which is susceptible to the a strain but resistant to the p 
strain of the fungus. Thus, only the a strain of the disease-producing 
organism was concerned in the cross. Of 1,970 F 2 plants which 
were inoculated, 1,471 showed resistance and 499 susceptibility to the 
disease under discussion. These results approximate closely a 3 : 1 
ratio between resistance and susceptibility, with resistance dominant. 
This ratio is also borne out by the progenies of a number of second 
generation plants that were grown thru to the third generation before 
being inoculated. Approximately 25 percent of these third genera- 
tion families bred true for resistance, 50 percent gave both resistant 
and susceptible plants, and approximately 25 percent bred true for 
susceptibility. The actual results by families were as follows : 9 homo- 
zygous resistant, 16 heterozygous resistant, and 11 susceptible. 

The following tables present second generation results of plants 
grown and inoculated during the summer of 191 9. 



Table i. — Additional F 2 data (1919) on crosses involving the a strain of 

anthracnose. 



Pedigree No. 


Parentage of hybrids. 


Resistant. 


Susceptible. 


5480 


Wells' Red Kidney X Robust 


216 


85 


5481 


Do. 


66 


16 


5482 


Selection B X Robust 


1 135 


55 


Totals 

Expected numbers 


417 
429.75 


156 
143-25 



Difference I 12.75 ±6.99 



The parentage of the crosses reported in Table 1 is exactly the 
same, with one exception, as that of the hybrids spoken of in the in- 
cluded summary of the previous paper. This exception is the use of 
selection B as the resistant parent instead of Wells' Red Kidney. 
This selection was a White Marrow bean from one of the families 
mentioned in the summary as being homozygous resistant for an- 
thracnose. The results obtained approach, within twice the probable 
error, a 3 : 1 ratio with resistance dominant which, in accord with pre- 
vious results, indicates a single factor difference concerned in the pro- 
duction of resistance to the a strain of the anthracnose fungus. 

The majority of the crosses listed in Table 2 were between selection 
B, which is resistant to both a and 6 strains of anthracnose, and two 
varieties of wax beans that are susceptible to both of these strains 
(2). Two families are also included in which one parent is resistant 
to only the a strain and the other parent to only the /? strain of an- 
thracnose. In all of these crosses, therefore, unlike the cases hereto- 



1 8 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 2. — F, data (1919) on crosses in which both the a and /3 stra'.ns of the 
antkracnose fungus were presumed to be present. 



Pedigree No. 


Parentage of hybrids. 


Resistant. 


Susceptible. 


Total. 


5471 


German Wax X Selection B 


13 


29 


42 


5472 


Do. 


26 


38 


64 


5485 


-DO. 


32 


27 


59 


5473 


Ward well's Wax X Selection B 


62 


43 


J 05 


5474 


Do. 


151 


59 


210 


5486 


Do/ 


14 


20 


34 


5557 


Do. 


26 


21 


47 . 


5558 


Do. 


82 


69 


151 


5483 


Robust X White Marrow 


2l6 


158 


374 


5484 


Do. 


90 


54 


144 


Totals of all p 


lants 


712 


5i8 


1.230 


Expected numbers (9 : 7 ratio) 


692 


538 




Difference 




20 ± 11. 7 





fore reported, both strains of anthracnose were presumed to be in- 
volved. 

Since the earlier results indicated that a single pair of genetic factors 
is concerned where either the a or ft strain is alone involved, a 9 : 7 F 2 
ratio is to be expected where both strains are involved. This theo- 
retical expectation is approached closely in all cases except in pedi- 
grees No. 5471, 5472, and 5474, in which cases the deviations from 
expectation are considerably more than three times the probable error. 
In the first two of these exceptional cases the numbers are perhaps 
too small to afford wholly trustworthy indications. In the case of 
ree No. 5474, however, with a total of 210 plants, there can be 
no doubt that the observed numbers do not fit a 9 : 7 ratio, as the de- 
viation from such a ratio is over six times the probable error. The 
observed ratio of 151 : 59 deviated from a 3 : 1 ratio by less than twice 
the probable error. While no direct test of the matter has been made 
it would seem possible that some individuals of Wardwell's Kidney 
Wax, which was the susceptible parent used in this case, might be 
resistant to either the a or the ft strain of the anthracnose fungus. If 
thi- were true, crosses involving such plants should result in 3:1 
rather than 9:7 F 2 ratios. 

Another possible source of deviation lies in the fact that it is very 
difficult to obtain uniform conditions for infection in all parts of a 
large outside inoculation chamber. As it is possible to infect the re- 
sistant Well-' Red Kidne) under the most favorable conditions, it 
would M-em reasonable to expect thai in certain sections of the inocu- 
lation chamber conditions would be favorable enough to infect some 
plants that would otherwise be classed as resistant. On the other 
hand, certain sections might prescnl conditions unfavorable for infec- 



m'rostie: disease resistance of beans. 



19 



tion and plants in such sections would be classed as resistant even tho 
they belonged to the susceptible class. That the deviations in the 
three pedigrees under discussion may be due to this cause is indicated 
by the fact that in the first two pedigrees mentioned there are too 
many susceptible plants while in the third pedigree there are too few 
susceptible plants. With the exception of the three pedigrees already 
discussed, the ratios listed in Table 2 only deviate from a 9 : 7 ratio 
by considerably less than three times the probable error. This is true 
in the cases where one parent is resistant and the other parent suscep- 
tible to both the a and the p strains of the anthracnose fungus and 
also in the cases of pedigrees No. 5483 and 5484 where one parent is 
resistant to only tjie a and the other parent resistant to only the /? 
strain of this fungus. Grouping all of the pedigrees together the 
totals again approach closely to a 9 : 7 ratio with resistance dominant. 

As a further check on the resistance of the families recorded as 
homozygous resistant in the summary of previous work, fourth gen- 
eration plants from two of these families were crossed with the homo- 
zygous resistant parent Wells' Red Kidney. The progenies of these 
crosses both in the first and second generation showed as marked re- 
sistance as either parent, thus lending further proof to the first as- 
suption that the families from which they came were homozygous 
for resistance.. 

INHERITANCE OF RESISTANCE TO THE BEAN MOSAIC ORGANISM. 

Bean mosaic is a disease that has come into prominence only in late 
years. As yet its cause remains in the same category as that of the 
mosaics of other plants, namely, not proved. For a description of this 
disease as it occurs on the bean, the reader should consult Reddick 
and Stewart (8). 

Material and Methods.— In the published inoculation results with 
bean mosaic one variety of pea bean stands out distinctly as being re- 
sistant to this disease (9, id). This variety is the Robust bean ob- 
tained originally from the Michigan Agricultural Experiment Station 
and grown for a number of years by the Plant Breeding Department 
of Cornell University under the accession number 1986/ This bean, 
because of its high degree of resistance and its good yielding qualities, 
was chosen as the resistant parent for hybridization work. The sus- 
ceptible parent used almost exclusively was the Flat Marrow, which 
is highly resistant to root-rot but very susceptible to mosaic. 

A large number of reciprocal crosses between these two varieties 
of beans were made in the Plant Breeding greenhouse during the 



20 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



winter of 1917-18. The F t plants were grown in the Plant Breeding 
garden during the summer of 1918 under a screen of mosquito bar to 
guard against cross-pollination by insects. A number of F 2 plants 
from these crosses were grown and inoculated in the greenhouse dur- 
ing the spring of 1919. The F 3 plants from these along with the addi- 
tional F._, plants were grown at Perry, N. Y,, during the summer of 
1 91 9. Inoculation in the greenhouse was carried out by hand, the 
method used being to rub vigorously the primary leaves of the plants 
to be inoculated with affected leaves from plants already showing this 
disease. For inoculation in the field every third row was planted with 
seed from badly diseased plants. A large percentage of this seed pro- 
duced mosaic offspring. The causal factor of the mosaic w r as con- 
veyed from the diseased rows to the healthy rows on either side evi- 
dently by natural agencies. It seems probable that insects played an 
important part in this respect as there seemed to be a correlation be- 
tween the number of insects present in any field and the rate and ex- 
tent of the dissemination of this disease. 

Inspections were made at various times during the growing season 
and final judgment was not passed on any plant until the end of its 
growth period. 

Genetic Behavior in — The crosses reported in Table 3 were all 
F, hybrids between varieties susceptible to mosaic and the Robust 

TABLE 3 — Degree of infection of mosaic on F x plants. 



Degree of 

Pedigree No. Parentage of hybrids. infection. 

i<yj Robust X Flat Marrow b 

107 Do b 

104 Do b 

90 Flat Marrow X Robust e 

85 Do b 

84 Do b 

83 Do d 

81 Do „ d 

79 ,.*.., Do d 

60 Robust X Selection B • d 

59 Do d 

51 Selection B X Robust d 

50 Do b 

42 Robust X Flat Marrow 1) 

23 Do b 

10 Do b 

X Wells' Red Kidney X Robust b 



■ Thi letteri ;i to < indicate Pitying degreei of infection, a indicating no 
infection and c severe infection. 



m'rostie: disease resistance of beans. 



21 



Pea bean, which is highly resistant to this disease. No artificial inocu- 
lations were made, but there was a plentiful supply of mosaic plants 
in the near vicinity and the causal organism was carried to the hybrid 
plants by some natural means. Artificial inoculation of these hybrid 
plants was not resorted to because of the fact that plants showing bad 
mosaic often yield only a small number of seeds, sometimes none at 
all, and it was necessary to secure as large a number of seeds as pos- 
sible for second generation plants. 

The degree of infection showed a marked variation, probably due 
to varying amounts of inoculation or to the age of the plant when 
inoculation occurred. The fact, however, that so many of the families 
showed mosaic to a greater or less degree indicates susceptibility to be 
as least partially dominant over resistance in the crosses recorded. 

Results in F, and F 3 . — Of the 191 F 2 plants classified as showing 
mosaic, 34 plants which showed only slight symptoms of mosaic gave 
Fo families which did not show this condition. On the other hand, 37 
of the 141 F 2 plants classified as showing no mosaic gave evidence of 
this disease in the F 3 families. This evident deviation from expected 
results may be explained in part by several involved conditions. In 
the first place, the presence of intergrading forms in the second gen- 
eration hybrids of this cross coupled with the fact that the resistant 
parent involved has a peculiar wrinkling of its leaves at certain stages 
not unlike a slight infection of mosaic, makes the definite determina- 
tion of such forms somewhat difficult. In the second place, it is dif- 
ficult to secure 100 percent infection even under the most favorable 

Table 4. — Inoculation results of F« plants from the Robust Pea bean X Flat 
Marrow and its reciprocal hybrid grown in the greenhouse and 
their F 3 progeny grown in the field. 

F 2 RESULTS (BY PLANTS) 





Mosaic. 


Plants badly infected 
No mosaic. (included under 
mosaic). 


Observed numbers 

Expected numbers (on 9 : 7 ratio) 


I 9 I 
186.8 


141 22 
145.2 21 


Difference 


4.2 ± 6.1 




F 3 RESULTS (BY FAMILIES) 








Observed numbers 

Expected numbers (on 9 : 7 ratio) 


179 130 
173-8 135.2 


20 
19 




5-2 ± 5 9 







22 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

greenhouse conditions. A few families might easily have escaped 
infection in this instance as these F 3 plants were not grown at the 
Perry Laboratory grounds where insects were plentiful but in the 
center of a large bean field where insects of all kinds were scarce. 
The percentage of mosaic plants in the inoculating rows was also 
much lower in this field than on the laboratory grounds. 

The resistant parent of the second generation plants listed in Table 
5 was either the Robust Pea bean or the ordinary White Marrow 
reported by Reddick and Stewart (9, 10) as showing at least partial 
resistance to mosaic. The susceptible parent in most cases was the 
Flat Marrow, which shows extreme susceptibility to this disease. The 
great majority of the crosses were between the Robust and Flat Mar- 
row types, the significance of which fact will be discussed later. 

The totals of the resistant and susceptible plants listed in Tables 4 
and 5 approach very .closely to a 9 : 7 ratio, with susceptibility domi- 
nant. A wide deviation from such a ratio will be noticed in individual 
cases thruout the tables, more especially where the smaller numbers 
are concerned. Such a deviation in individual cases might be ex- 
pected, due to the small numbers in some of the families and to the 
fact that it is very difficult to obtain a uniform inoculation in all parts 
of a field. The totals of all of the plants involved rather than the 
totals of any particular family should, therefore, offer a more ac- 
curate interpretation of the results obtained. This is especially so 
where the total numbers reach the proportion, of those reported in 
Table 5. 

In view of the ratio. reported, we must assume that two factors are 
concerned in producing susceptibility or resistance to this disease. 
The presence of both of these factors in the dominant condition goes 
to make susceptibility. The presence, on the other hand, of one or 
' K 'th o! their recessive allelomorphs in the homozygous condition 
lend- to produce a plant that is resistant to the disease in question. 

Plants homozygous for both dominant factors might be expected 
to show a greater degree of susceptibility than plants heterozygous 
for one or both of these factors. Similarly, plants heterozygous for 
only one of tin- dominant factors might be expected to show a greater 
degree of susceptibility than plants heterozygous for both of these 
factors. If these assumptions are correct, a gradation in resistance 
would be expected. Hants homozygous for the recessive allelomorphs 
WOUld be expected to show as great resistance as the resistant parent 
and greater resistance than plants homozygous for one recessive allelo- 
morph or plants heterozygous for one recessive allelomorph and 



m rostie: disease resistance of beans. 



23 



Table 5. — Inoculation results of F, plants grown at Perry, N. Y. 



rcuigicc ±>l>. 


Plants showing- 


Pedigree No." 


Plants showing — 


Mosaic. 


No mosaic. 


Mosaic. 


No mosaic. 


4461* 


38 


33 


4533 


7 


6 


4462* 


32 


3i 


4534 


5i 


47 


4463 


2 





4535 


67 


39 


4464 


I 


1 


4537 


23 


15 


4466 


I 





4538 


17 


1 1 


4470* 


2 


3 


4539 


50 


41 


4471* 


8 


11 


4540 


23 


20 


4472* 


13 


10 


4541 


36 


27 


4478* 


12 


15 


4542 


38 


32 


4479* 


5 


6 


4543 


20 


13 


4480* 


12 


10 


4544 


22 


17 


4481* 


12 


20 


4545 


16 


13 


4482* 


10 


15 


4546 


17 


12 


4483* 


61 


50 


4547 


61 


49 


4484* 


34 


23 


4548 


6 


3 


4485* 


28 


16 


4549 


4i 


20 


4486* 


27 


20 


4550 


38 


30 


4487* 


4 


1 


4551 


74 


62 


4488* 


26 


20 


4552 


46 


34 


4489* 


. 67 


54 


4553 


35 


30 • 


4490* 


21 


17 


4564 


4i 


34 


4491* 


14 


6, 


4569 


12 


9 


4500 


3 


2 


4570 


IS 


21 


4503 


45 


38 


457i 


20 


14 


4504 


30 


34 


4572 


23 


17 


4505 


57 


40 


4573 


22 


16 


4506 


30 


29 


4574 


14 


10 


4507 


25 


18 


4575 


22 


20 , 


4508 


9 


6 


4578 


37 


30 


4509 


28 


25 


4579 


60 


39 


4510 


28 


20 


458i 


28 


20 


4511 


5 


3 


4582 


50 


38 


4512 


28 


18 


4586 


38 


32 


4513 


28 


22 


4587 


38 


30 


4514 


58 


42 


4593* 


36 


26 


4515 


25 


17 


4594* 


30 


18 


4516 


4 


2 


4595* 


23 


18 


4517 


48 


40 


4598 


15 


16 


4519 


2 


1 


4599 


25 


24 


4520 


2 


2 


4600 


40 


32 


4521 


20 


11 


4601 


29 


21 


4522 


18 


11 


4602f 


34 


24 


4523 


16 


11 


4604! 


8 


3 


4524 


30 


18 


4608! 


19 


12 


4525 


4 


2 


46nf 


30 


21 


4526 


33 


24 


4613 


■ 78 


51 


4527 


8 


9 


46i4f 


43 


30 


4528 


24 


16 


46i5t 


45 


38 


4529 


47 


39 


46i6f 


63 


38 


4530 


32 


27 


46i7t 


38 


26 


4531 


70 


63 


4634 


64 


43 


4532 


24 


18 


4635 


43 


28 



Observed numbers 

Expected numbers (on 9 
Difference 



7 ratio) 



2,982 2,290 
2,965.5 2,306.5 
16.5 ± 24.3 



Total number of plants tested 5,272 

Number of plants severely infected with mosaic 335 

Expectancy on a 9 : 7 hypothesis 330 

Difference 5 + II.8 

The parentage of the hybrids listed in Table 5 is as follows : Numbers un- 
marked, Flat Marrow X Robust; Numbers marked *, Flat Marrow X Marrow 
Numbers marked f, Wells' Red Kidney X Robust. 



24 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



homozygous for the other. Thus, we see that almost a complete 
gradation would be expected from plants completely resistant to 
plants wholly susceptible. Such a gradation of forms actually occurs 
and is one of the difficulties in the way of obtaining accurate counts 
on resistant or susceptible plants, as the intermediate forms showing 
either partial resistance or partial susceptibility are difficult to distin- 
guish from each other. 

One of the methods of checking the two-factor hypothesis assumed 
in this case was to make accurate counts on the number of plants 
severely infected with mosaic. One sixteenth of the total number of 
plants would be the expectancy and this proportion is approximated 
very closely in all of the observed results. Furthermore, so far as 
tested, Fo plants which were severely infected in all cases produced 
severely infected F 3 progenies. 

With a two-factor hypothesis such as has been advanced to account 
for resistance or susceptibility to mosaic, we might expect to find some 
commercial types of beans which would belong to some of the classes 
intermediate between these two conditions. 

Inoculation experiments (9, 10) have shown that varieties of beans 
differ considerably in the extent to which they become infected. In 
further inoculation work with hybrids of different parentage from 
those recorded in the present paper a different ratio might, therefore, 
be expected. For example, if a plant homozygous for only one of 
the recessive allelomorphs was crossed with the Robust type, assumed 
to be homozygous for both of these factors, a simple 3: 1 ratio would 
he expected. The fact that the great majority of the crosses reported 
at this time were between the same two parents obviates the possi- 
bility of such ratios confusing the results when all classes of crosses 
arc grouped together. 

INHERITANCE OF RESISTANCE .TO THE BEAN ROOT-ROT FUNGUS. 

The root rot referred to in this article is the dry root rot caused by 
Fusarium martii phdseoli Burk. It has become widespread enough to 
be of considerable economic importance in the bean-growing sections 

of N'rw York. This disease has recently been studied in detail by 
Burkholder and a full account of its life history and appearance on 

the bean plant may be obtained by consulting his paper (5). 

Material and Methods, tn fields of White Marrow beans there 
Often Can be observed, especially toward the end of the growing sea- 
son, a few plants of a mon vdgorOUS growth and darker green color 
than the typical marrow plants. Tliis is the Flat Marrow bean de- 

• bed by liurkhnldcr as being resistant to the dry root rot. Unfor- 



m'rostie: disease resistance of beans. 



25 



tunately, it matures too late for commercial purposes but on account 
of its root-rot resistant qualities it was chosen as the starting point 
for the breeding of beans resistant to the root-rot fungus. The sus- 
ceptible parent used in the greater number of the crosses was the 
mosaic resistant Robust Pea bean which matures considerably earlier 
than the- Flat Marrow. 

The crossing, as in the previously reported cases, was done almost 
exclusively in the Plant Breeding greenhouse at Cornell University. 
The first generation of all the crosses was also grown under the bean 
screen in the Plant Breeding garden at the University. The second 
and subsequent generations were grown on the grounds at the Bean 
Laboratory, Perry, N. Y. The soil on the laboratory grounds, besides 
being plentifully supplied in the beginning with the causal organism 
of the dry root rot, is reinoculated each year at planting time. The 
method followed is to make a spore suspension of the causal organism 
in water and dip the beans in this before planting. The seed while 
still wet is planted in damp soil. By this method the field is evenly 
inoculated. 

Genetic Behavior in F x . — No artificial inoculations of F x plants 
were made because of the large decrease in yield of plants badly af- 
fected with root rot. There was, however, a plentiful supply of the 
bean root rot organism present in several parts of the ground occupied 
by the F 1 plants. On these sections the roots of the hybrids became 
infected, thus indicating susceptibility to this disease to be at least 
partially dominant over resistance. 

Results in F 2 and F 3 . — In presenting the following F 2 and F 3 data 
on the inheritance of susceptibility to root rot it must be borne in mind 
that in studies of this kind a certain arbitrary standard must be set up 
to constitute a dividing line between resistance and susceptibility. 
The results obtained and their interpretation will depend largely on 
where such a dividing line is placed. For the plants under discussion 
in this paper, the dividing line chosen was, as far as could be deter- 
mined, midway between the condition of the roots of the plants show- 
ing greatest infection during any particular season and the normal 
condition of healthy roots. 

The proof or disproof of any hypothesis advanced to account for 
the inheritance of susceptibility to root rot requires a considerable 
amount of careful checking in later generations. All that is offered, 
however, in the following pages is a statement of the results obtained 
according to the classification used, with a tentative factorial explana- 
tion of such results as were recorded for the few generations grown. 



26 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The plants listed in Table 6 were all F 2 segregates of crosses be- 
tween strains of beans resistant to root rot and strains which showed 
susceptibility to this disease in previous inoculation experiments. The 
resistant parent used almost exclusively was the Flat Marrow, the 
only exception to this being in a few cases where a pea bean selection 
which had shown considerable resistance w r as used in place of the 
Flat Marrow. 



Table 6. — F. 2 (1918) inoculation results on bean hybrids to determine resistance 

to dry root rot. 







Condition of the roots. 


Pedigree No. 


Parentage of hybrids. 


Medium to 


Medium to 






severe infection. 


no infection. 


1592 


Flat Marrow X Robust 


4 


3 


1591 


Flat Marrow X Manchurian Pea 


3 


3 


1590 


Do. 


3 


A 

*r 


1585 


Flat Marrow X Manchurian Cranberry 


5 


4 


t -8 1 


Flat oA arrow X Marrow 


8 


6 


1583 


Flat Marrow X B 39 


12 


10 


1581 


Flat Marrow X B 20 


9 


6 


1579 


Pea (Dye) X B 126 


2 


1 


1576 


Marrow X Flat Marrow 


6 


5 


1565 


Flat Marrow X Marrow 


8 


5 


1564 


Flat Marrow X Robust 


12 


9 


1562 


Do. 


13 


12 


1561 


Do. 


19 


11 


1560 


Wells' Red Kidney X Flat Marrow 


9 


7 


1559 


Flat Marrow X Robust 


8 


5 


1558 


Robust X Flat Marrow 


5 


5 


1557 


Do. 


6 


3 


1556 


Do. 


16 


7 


1555 


Robust X Pea (Dye) 


8 


11 


1553 


Do. 


30 


14 


1552 


Pea (Dye) X B 126 


13 


10 


1551 


Robust X Flat Marrow 


14 


18 


1550 


Flat Marrow X Robust 


10 


10 


1548 


Pea (Dye) X Marrow 


11 


7 


1539 


Flat Marrow X B 39 


13 


11 






247 


187 




Expected numbers (on 9 : 7 ratio) 


244.1 


1 80.9 




Difference 


2.9 rfc 6.2 



I he numbers of plants arc not large enough to be of significance in 
the individual families. Taken collectively, however, the results ap- 
proximate, within the limits of probable error, a ()\/ ratio with sus- 
ceptibility dominant. It is also true that the totals agree closely with 
a 37:37 ratio. With such a ratio, however, the 27 class would be the 
dominant ela and as the smaller class is the resistant class in this 
lam e bould be dominant in the firgl generation, an assump- 
tion which is not supported by the observed results. 



m'rostie: disease resistance of beaxs. 



27 



Table 7 presents the F 3 inoculation results of several of the F 2 
families listed in Table 6. On account of the dry season in 191S, 
coupled with severe root-rot infection and an early frost, a great many 
of the plants listed in Table 6 did not produce seed. This was particu- 
larly the case with the plants badly affected with root rot : hence Table 
7 represents only F 3 families from the rather small percentage of F 2 
plants that produced seed. 



Table 7. — Results of inoculating F 3 (1919) progenies of F a plants listed in 

Table 6. 



*■ 

Pedigree 
No. 


F3 families from plants showing medium 
to severe infection in Fj. 


F3 families from plants showing medium 
to no infection in F*. 


Breeding true. 


Breaking up. 


Breeding true 


Breaking up. 


1539 


2 


4 


4 


I 


1550 


I 


7 


10 





1551 


O 





18 


O 


1553 








14 







I 


6 


10 


I 


1558 


I 


3 


5 


O 


1560 


O 





1 


O 


1561 


3 


16 


7 


O 


1562 


2 


7 


12 





1576 


2 


4 


3 





1579 


1 





1 





1583 


1 


3 


7 





1584 


1 


5 


3 





1585 





2 


4 





1591 





3 


3 





1592 





2 





I 


15 


63 


102 


3 



The object of testing these families in the third generation was to 
find out which of the general classes under which these plants had 
been listed broke up in the next generation. If the families from F 2 
plants which were grouped under medium to no infection broke up. 
it would indicate that the two-factor hypothesis assumed was not 
correct. On the other hand, if the families from F 2 plants which had 
been classed as medium to severe infection broke up. it would be in 
accord with such an hypothesis. An examination of Table 7 shows 
that the plants listed as medium to no infection in the F 2 produced 
progeny which, in almost every case, bred true to this condition. On 
the other hand, a large number of the progeny of the F 2 plants listed 
as medium to severe infection broke up in the F 3 . It is true that a 
higher percentage of families from this class bred true than would be 
expected on a 9 : 7 hypothesis. This deviation from expected results 
may be explained, in part at least, by two disturbing conditions. The 



28 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

Table 8. — Results of root-rot inoculation on F, (1919) plants grown at 



Perry, N. Y. 





Condition of the roots. 




Condition of the roots. 


PedigTee Xo. a 


Medium to 


Medium to no 


Pedi ree No 
e« igree . o. 


Medium to 


Medium to no 




severe infection. 


infection. 




severe infection. 


infection. 


4443* 


12 


7 


4528 


24 


21 


4444* 


3 


1 


4529 


53 


41 


444>* 


2 


2 


4530 


34 


28 


4446* 


I 


1 


4531 


80 


68 


4447* 


3 


2 


4532 


25 


22 


4448* 


3 


1 


4533 


8 


7 


4450* 


3 


2 


4534 


53 


45 


445 1* 


3 


3 


4535 


62 


60 


1 1 - ->* 

44;>-* 


2 


2 


4537 


20 


17 


44: >4* 


8 


4 


4538 


16 


16 


4455* 


4 


4 


4539 


60 


53 


1 1 -f * 

44^°* 


4 


3 


4540 


28 


19 


• « - -4. 

44.S/T 


12 


5 


4541 


36 


33 


4-o°T 


48 


31 


4542 


38 


30 


1 (At 4 

44'' 1 T 


42 


36 


4543 


17 


14 


44U2T 


37 


30 


4544 


22 


18 


44 f) / + 


33 


21 


4545 


16 


12 


44°»J 


5« 


44 


454" 


15 


15 


44 9 t 


18 


16 


4547 


66 


54 


44"of 


3 


2 


4548 


4 


3 


4 1 - 1 4- 

44/ it 


11 


9 


4549 


36 


26 


447 2 t 


10 


8 


4550 


39 


32 


44/3T 


13 


1 1 


4551 


72 


60 


4474* 


4 


3 


4552 


49 


34 


4475* 


15 


9 


4553 


38 


34 


44 / °* 


37 


24 


4556 


58 


48 


4477* 


26 


18 


455 7 1 


38 


32 


44 / °t 


17 


13 


4558J 


26 


23 


4479t 


1 


4 


4564 


44 


36 


A lXfl + 

44° ,J T 


17 


11 


4565t 


63 


5 fi 


11X1 + 

44° 1 T 


15 


1 2 


45<'><'>t 


24 


20 


1187 + 

44"* T 


1 6 


13 


45"7t 


' 33 


19 


i tX i + 

44°3T 


67 


51 


4568 


22 


16 


\ iX 1 + 

44°4T 


38 


24 


4 5 "9 


10 


10 


4 iXc 

44°5 


24 


20 


4570 


2 1 


18 


W[ 


30 


22 


4571 


19 


16 


44«7t 


4 


3 


4572 


28 


21 


448«t 


26 


21 


4573 


24 


13 


4489 t 


70 


54 


4574 


13 


13 


449" t 


23 


17 


4575 


26 


19 


4491 t 


13 


EO 


4578 


40 


35 


4507 


30 


24 


4579 


59 


46 


4509 


31 


2 5 


458i 


26 


22 


4512 


25 


20 


4582 


48 


43 


4513 


30 


23 


4583 


15 


12 


45U. 


66 


5i 


4584 


14 


12 


4515 


22 


21 


4585 


55 


46 



"The parental of the hybrids listed 111 Table 8 is as follows: Numbers un- 
marked. Mat Marrow / Robust ; Numbers marked *, Flat Marrow X Wells' 
N'-d K umbers marked t, Flat Marrow X Marrow; Numbers marked $, 

Flat Marrow X Medium. 



m'rostie: disease resistance of beans. 



29 





Condition of the roots. 




Condition of the roots. 


Pedigree No. 


Medium to 


Medium to no 


Pedigree No. 


Medium to 


Medium to no 




severe infection. 


infection. 




severe infection. 


infection. 


4516 


5 


2 


4586 


38 


33 


4517 


54 


44 


4587 


41 


34 


4519 


2 


1 


4593t 


32 


25 


4520 


2 


1 


4594t 


32 


25 


4521 


18 


15 


4595t 


25 


20 


4522 


17 


14 


4598 


20 


13 


3423 


16 


12 


4599 


28 


24 


4524 


29 


23 


4600 


42 


38 


4525 


3 


4 


4601 


30 


23 


4526 


29 


22 


4613 


70 


56 


4527 


10 


9 








Observed numbers 






3-147 


2.514 


Expected numbers (on 9 : 7 ratio) 




3.I84-3 


2,476.7 


Difference , , , 








37-3 ± 25.4 



first is the difficulty of securing an even infection in all parts of the 
field. As far as possible the same rate of inoculation is maintained in 
all parts of the field but local soil conditions vary so much that the 
rcot-rot organism multiplies much more rapidly in some parts of the 
field than in others ; hence the unevenness of infection. Probably a 
still more disturbing factor is the fact that root-rot infection is much 
more severe in some seasons than in others. In the summer of 191 8 
infection was much more severe than in the summer of 1919. This 
seasonal variation makes necessary a revised classification for each 
y r ear. The dividing point between resistance and susceptibility must 
necessarily be different with each classification and this constitutes a 
possible source of error. The classification for resistance is more ex- 
acting when infection is less severe ; hence it is quite possible that a 
number of the families classified in Table 7 as breeding true for sus- 
ceptibility should have had some of their plants placed in the medium 
to no infection class, which would place them in the class which did 
not bred true and thus bring the results closer to the theoretical ex- 
pectancy. 

The data listed in Table 8 are all second generation inoculation re- 
sults of crosses between the root-rot resistant Flat Marrow and varie- 
ties of beans susceptible to this disease. The dominating cross is the 
Flat Marrow by the Robust Pea bean. Many of the individual family 
ratios, as well as the totals for all of the families, approximate very 
closely the 9 : 7 ratio obtained with the earlier inoculations reported 
in Table 6. The large numbers of individuals listed in Table 8, taken 
with the closeness with which the totals of the inoculation results ap- 
proach a 9 : 7 ratio, give added support to the assumptions, first, that 



30 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



susceptibility to root rot is partially dominant to resistance to this dis- 
ease and. second, that the results obtained are to be explained on a 
two-factor hypothesis. 

As is the case with mosaic of the bean, various degrees of resistance 
and susceptibility to root rot have been observed in different bean 
varieties. Different ratios might be expected here also if parents of 
varying degrees of resistance and susceptibility were used, so that re- 
sults similar to the ones here reported could only be expected when 
parents of a similar genetic constitution with respect to root rot re- 
sistance were used. 

Discussion. 

The inheritance of the ability of a plant to withstand the attacks of 
any particular disease-producing organism is a factor of prime impor- 
tance in the production of disease-resistant varieties. A knowledge 
of the exact manner of this inheritance is also of great value, as such 
knowledge saves considerable time and unnecessary labor in obtaining 
the desired results. The investigations reported in this paper had for 
their objects, therefore, the twofold purpose of studying the method 
of inheritance of disease resistance and of* obtaining at the same time 
varieties of beans resistant to the three diseases concerned. 

From the families reported as homozygous resistant to anthracnose 
in the summary of previous work done, a number of white-seeded re- 
sistanl strains have been isolated, some of which givepromise of being 
desirable commercial types. One of the parents involved in this cross 
was also resistant to mosaic and some of the selected types are showing 
resistance to both mosaic and anthracnose. The majority of the 
crosa - made in connection with the studies of the inheritance of sus- 
ceptibility to both root rot and mosaicrwere reciprocal crosses between 
the root rot resistant Flat Marrow and the mosaic resistant Robust 
Pea bean. Both of these strains of beans arc also resistant to the p 
Strain of the anthracnose fungus which is the strain most commonly 
found in the bran-growing sections of the State. A few hundred F a 
plant- have been selected from this cross which do not show either 
root rot or mosaic and all of which should be resistant to the fi strain 
of the anthracnose fundus. Of cour.se, further testing will have to be 
done to check the resistance of these selected strains to the root rot 
and mosaic organisms, but the c hances are good of some of them con- 
tinuing to show resistance to these two diseases. Only high yielding 
plants which had matured all of their pods were selected so that any 
of these selected trail hould make desirable commercial types even 
apart from their evident disease resistance. 



M rostie: disease resistance of beans. 



31 



Some F 2 plants were also selected from reciprocal crosses between 
the Flat Marrow and the ordinary White Marrow. As mentioned 
before, the Flat Marrow is resistant to root rot and to the (3 strain of 
the anthracnose fungus, while the W hite Marrow is resistant to the a 
strain of the anthracnose fungus and at least tolerant to mosaic (9, 
10). From this combination of parents there is a chance of securing 
progeny resistant to all three diseases. The magnitude of this chance 
naturally depends on the number of factors involved in resistance to 
the different diseases in question. The F 2 plants selected from this 
cross did not show either mosaic or root rot and, as 9 out of every 16 
of these plants should possess either homozygous or heterozygous re- 
sistance to the anthracnose fungus, the chances are good of obtain- 
ing the desired results. 

Summary. 

Investigations of the inheritance of resistance to the bean anthrac- 
nose fungus indicate a single factor difference between resistance and 
susceptibility where only the a strain of the fungus is concerned in 
the cross. Where both the a and (3 strains are concerned a two-factor 
difference is indicated and a 9 : 7 ratio in F 2 is obtained. In both in- 
stances resistance is dominant over susceptibility. 

F 1 and F 2 results of crosses involving the inheritance of suscep- 
tibility to the bean mosaic organism indicates a partial dominance of 
susceptibility over resistance to this disease. A two-factor hypothesis 
is advanced to account for the inheritance of resistance and suscep- 
tibility. Such an hypothesis is borne out by the totals of the observed 
F 2 ratios between resistant and susceptible plants and by the fact that 
approximately one sixteenth of these F 2 plants were severely infected 
with mosaic and bred true for this character in the F 3 . 

Inoculation results of F 2 hybrids from crosses involving the inheri- 
tance of susceptibility to root rot indicate susceptibility to this disease 
to be dominant over resistance. That this was the case had. been in- 
dicated by the fact that a few F x plants, which had been grown on in- 
fested ground, showed good infection. 

A tentative two-factor hypothesis to account for the inheritance of 
susceptibility to root rot, with a 9:7 ratio in the F 2 between suscep- 
tible and resistant plants, is advanved to explain the results obtained. 
The fact that the susceptible plants were in the majority in the F 2 
and that a large number of the F 3 families from these plants did not 
breed true while the F 3 families from resistant F 2 plants in almost all 
cases bred true, is in accord with the hypothesis advanced. 

The necessity of establishing an arbitrary dividing line between 



32 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



resistant and susceptible forms adds considerable difficulty to the 
proving of any hypothesis to account for the inheritance of suscep- 
tibility to bean root rot. 

A number of promising strains of beans have been isolated which 
show resistance to anthracnose. A few hundred heavily podded F 2 
types have been selected which show resistance to both root rot and 
mosaic and which should also be resistant to the j3 strain of the an- 
thracnose fungus. Further testing should isolate some very desirable 
resistant commercial types from these selections. 

Literature Cited. 

1. Barrus, M. F. An anthracnose resistant Rid Kidney bean. In Phytopath., 

5: 303-311. figs. 1-4- 191 5- 

2. . Varietal susceptibility of beans to strains of Colletotrichum lindc- 

muthianum (Sacc. and Magn.) Bri. and Cav. In Phytopath., 8: 589-614. 
1018. 

3. Biffen, R. H. Mendel's law of inheritance and wheat breeding. In Jour. 

Agr. Sci.. 1 : 40-44- 1905. 

4. Burkholder. W. H. The production of an anthracnose resistant White 

Marrow bean. In Phytopath.. 8: 353-359. 1918. 

5. • The dry root-rot of the bean. Cornell Univ. Agr. Expt. Sta. Me- 
moir 26, p. 1003-1033. 1919. 

6 McRoSTIE, G. P. Inheritance of anthracnose resistance as indicated by a 
cross between a resistant and a susceptible bean. In Phytopath., 9: 141- 
14X. 1 91 9. 

7. NiLSSON-EHLE, H. Resistenz gegen Gelbrost be:m Weisen. In Kreusung- 

suntersuchungen an Hafer und Weisen. Lund's Universitets Arsskrift 
X. F, Afd. 2. 7: 57-82. 191 1. 

8. RlDDICK, I)., and Stewart, V. B. Bean mosaic. Abs. in Phytopath., 7: 

61. 1917. 

9 • Varieties of beans susceptible to mosaic. In Phytopath., 8: 530-534. 

1918. 

10. . Additional varieties of beans susceptible to mosaic. In Phytopath., 

9: 149-152. 1919- 

N STUCMY, H. I'. Transmission of resistance and susceptibility to blossom- 

d rot in tomatoes. Ga. A^r. Expt. Sta. Bui. 121, p. 83-91. 1916. 

W Tl DALE, W. II. FUu wilt. A study of the nature and inheritance of wilt 

resistance. In J<>nr. Agr. Research, 11: 573-606. 1917. 

13. Vavim.v. \. I Bret-fling for resistance to rust and mildew in wheat. In 
J<. nr. Genetics, 4: 49-65. 1914. 



SWAXS0X I HYDROCYANIC ACID IX SUDAN GRASS. 



33 



HYDROCYANIC ACID IN SUDAN GRASS AND ITS EFFECT 

ON CATTLE. 1 

C. O. Swaxsox. 2 

This paper is a preliminary report of work still in progress. It 
is planned to extend the investigation and to obtain additional data 
to confirm some of the results obtained. A number of observations 
reported in this paper are new only as to Sudan grass, several inves- 
tigators having made similar observations in connection with other 
plants. Citations to literature will be deferred to a future paper, as 
will discussion of theories. 

Sudan grass is one of the important forage crops in the Southwest. 
Occasional cases of poisoning have been reported. In August, 1919, 
a farmer near Abilene, Kans., lost several head of cattle, death ap- 
parently being caused by poisoning from Sudan grass. A sample of 
the grass sent to the laboratory was tested for hydrocyanic acid, but 
none was found. The grass was wilted and partially dry when ob- 
tained. Later experiments demonstrated that tests made on grass in 
this condition may be worthless. 

In the fall of 1919, the Dairy Department of the Kansas State Agri- 
cultural College used a plot of 5.4 acres of Sudan grass for pasturing 
six Holstein cows. The cows were in good condition and gave the 
usual amount of milk. Because of reported cases of poisoning from 
Sudan grass, it was thought worth while to test this grass for hydro- 
cyanic acid. 

All samples were hand picked, taken from various parts of this 
pasture in such size as the cows would gather. The samples were 
taken at once to the laboratory and passed thru a small feed cutter 
and a 5-liter flask rilled half full. To this was added enough water 
to cover the cut grass and acidified with sulfuric acid. About 400 
c.c. were distilled into a dilute solution of potassium hydroxid. To 
this was added a small amount of ferrous sulfate and hydrochloric 
acid to acid reaction and the solution warmed gently. The amount 
of hydrocyanic acid present was judged by the intensity of color. 
A deep blue indicated a large amount and a faint blue, a trace. This 

1 Contribution from the Department of Chemistry, Kansas Agricultural Ex- 
periment Station, Manhattan, Kans. Published by courtesy of the American 
Chemical Society. Paper read at the St. Louis, Mo., meeting, April, 1920. 
Received for publication September 11, 1920. 

2 Associate chemist. Kansas Agricultural Experiment Station. 



34 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



was the usual method of procedure when it was desired simply to 
learn if hydrocyanic acid was present. Modifications were intro- 
duced, as will appear, in order to show the effect of certain factors. 
No quantitative tests were made. 

The first sample was collected September 12. The test, made at 
once on the green grass, showed the presence of large amounts of hy- 
drocyanic acid. A portion of this sample was allowed to dry and 
this, when tested, gave only a faint trace. This suggested that the 
condition of the grass might have had something to do with the re- 
sults of the tests. Accordingly a number of experiments were made 
in order to determine the optimum conditions for making the test. 
It was found in all cases that the maximum amount of hydrocyanic 
acid, if present, was obtained when the test was made on the green 
material immediately after cutting. A sample picked in the afternoon 
would show a large amount of hydrocyanic acid in the portion tested 
at once, while in the portion kept till the next day, only a trace or 
none at all would be found. Such experiments with several minor 
modifications showed that if the tests were to have any value they 
must be made on the grass immediately after cutting. 

After these experiments had been performed, new samples were 
obtained from the field near Abilene where the poisoning had oc- 
CUired. W hile they had to be brought 40 miles, care was taken to 
prevent wilting. Large amounts were found, but apparently not 
larger than in several samples from the pasture on the Agronomy 
farm. 

The rate of drying is important. Samples were divided into sev- 
eral portions. ( )iic was dried slowly in the shade, one in the sun, one 
in an oven having a current of air heated to 70 , and on one the test 
was made immediately after cutting. The portion tested at once 
gave large amount-, that dried in the oven somewhat less, that dried 
in the Slin —till less, and that dried slowly in the shade none or only a 
trace. 

The addition of sulfuric acid is not necessary for the test if it is 
made at once on the green material. Samples were divided into 
three portion*. Sulfuric acid was added to one, hot water to another, 
while the third was digested in water al room temperature for sev- 
eral hour-. On distillation, the last fine gave larger amounts than the 
other two. 

1 ■ ample was divided into two portions. One portion was 

treated with chloroform by placing in a closed can for about an hour 

and then dried rapidly. The other portion was placed at once in the 



SWAXSOX : HYDROCYAXIC ACID IN SUDAN GRASS. 



35 



air oven and dried. The portion treated with chloroform gave the 
stronger test. 

These experiments make it appear that hydrocyanic acid is lib- 
erated by enzymes. If these are destroyed by the addition of hot 
water, sulfuric acid, or treatment with dry heat, not as much hydro- 
cyanic acid is obtained as when the tests are made at once on the 
green grass simply by digesting in water at room temperature and 
then distilling. 

Slow drying was not the only way in which the hydrocyanic acid 
would disappear. Samples of Sudan grass known to give strong tests 
for hydrocyanic acid were placed, without first passing through the 
feed cutter, in flasks and kept moist and green for several days. Tests 
by the use of sulfuric acid and by digesting in water failed to show 
any hydrocyanic acid present. This experiment was varied by pass- 
ing air continuously thru the flask, but the result was the same. Green 
samples were placed in an open pan and kept moist for about a day. 
This treatment apparently had no effect on the amount of hydro- 
cyanic acid obtained. It was not determined how long it would take 
under such conditions for the hydrocyanic acid to disappear. 

Converting Sudan grass into silage did not cause hydrocyanic acid 
to disappear. Samples were cut fine, packed tightly into milk bottles, 
and sealed. When two weeks old the bottles were opened and the ma- 
terial was excellent silage. One portion of this silage was digested 
in water and then distilled. Large amounts of hydrocyanic acid were 
found. The acid did not disappear rapidly from this silage. An- 
other portion was placed loosely in an open Mason jar and allowed to 
remain over night. On digesting in water and distilling, large 
amounts were found. 

While these tests were being made, the cows remained on the grass 
and apparently in good health. As these cows had been on this pas- 
ture form July to October, it was thought that the effect might be 
different if cows not used to Sudan grass were allowed to eat it. Ac- 
cordingly, on October 3, two other cows which had not eaten any 
Sudan grass were placed in this pasture. These cows seemed to 
suffer no ill effects. The grass was tested on this date and apparently 
contained as much hydrocyanic acid as at any time. 

Freezing Sudan grass did not diminish the amount of hydrocyanic 
acid obtained if the test was made before the grass thawed and wilted. 
A sample was frozen by placing over night in an ice machine. The 
temperature was about 20 F. One portion was cut at once, digested 
in water, then distilled. This gave a much larger amount than was 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



obtained on another portion which was allowed to wilt before.it was 
tested. Another portion was allowed to dry first and from this no 
hydrocyanic acid was obtained. 

The first killing frost of the season occurred October II. The cows 
were taken from the pasture the evening before, so no report can be 
made as to what the effect might have been if they had been allowed 
to remain another day. It was known, however, that some farmers 
in the neighborhood were pasturing cattle on Sudan grass at this par- 
ticular time and continued to do so beyond October 1 1. As far as is 
known, no ill effects were observed. While no tests had been made 
on any of these grasses yet the strong probability is that hydrocyanic 
acid was present. 

A sample of Sudan grass was obtained on the morning of October 
1 1 while the frost was still on the grass. The results on this sample 
were the same as from that frozen artificially. In the afternoon of 
the same day another sample was obtained. The grass was now 
wilted and black. This sample gave a very small amount of hydro- 
cyanic acid. On the next day another sample was gathered, and not 
a trace of hydrocyanic acid could be found. 

Sum alary. 

i. Hydrocyanic acid was found in large amounts in Sudan grass 
used for pasture and no harm resulted to the cattle. 

i. Liberation of hydrocyanic acid from Sudan grass is apparently 
iated with enzyme action. Digesting in water at room temper- 
ature for several hours and then distilling gave larger amounts of 
hydrocyanic acid than if sulfuric acid was added at once. Hot water 
and dry heat diminished the amount of hydrocyanic acid obtained. 
Slow drying caused the hydrocyanic acid to disappear. Tests made 
on wilted sample-, or those several days old may be worthless. 

Making Sudan grass into silage did not diminish the amount of 
hydrocyanic acid obtained. 

\. Test- made immediately on frosted Sudan grass gave very large 
amounts of hydrocyanic acid, hut it disappeared rapidly as soon as 
the plant began tO will ; when dry the hydrocyanic acid had disap- 
peared. 

While Sudan grass giving a strong test for hydrocyanic acid 

•rai no! harmful to cattle, under oilier conditions it was harmful. 
Immunity WIS not due to habituation. 



H ARTWELL & DAMON I IMPROVING A LIGHT SOIL. 



37 



SIX YEARS' EXPERIENCE IN IMPROVING A LIGHT, 
UNPRODUCTIVE SOIL. 1 

Burt L. Hartwell and S. C. Damon. 2 

The land upon which the experiment was conducted adjoins the 
college property on the north and was leased from E. Sweet. The 
soil is classified as Warwick sandy loam, of which there is consider- 
able easily tilled area in the State. The field had not been tilled, 
cropped, nor manured for many years. The turf had become very 
thin, and moss had taken the place' of grass to such an extent that a 
season's growth did not yield a quarter ton of hay. The subsoil was a 
coarse gravel, and leaching could take place readily. Aside from 
manurial requirements, the fundamental needs appeared to be for 
lime and for organic matter to conserve moisture. Six apparently uni- 
form, level plats of a quarter acre each were used in the experiment, 
which was begun in 191 3. 

The plan was to prepare in different ways for a uniform planting 
of potatoes in 191 7. with the hope that the effect of the various pro- 
cedures might be shown on this cash crop. Winter wheat was sown 
uniformly following the potatoes and harvested in 1918, after which 
the station gave up the land. The general cropping system followed 
on the different plats will now be described briefly. 

On plat 1, the plan was to grow on the acid soil such crops as might 
develop there, with the" main object of increasing the organic matter. 
They comprised lupine for green manuring, followed by rye as a 
cover crop, in 1913 : soybeans for green manuring in 1914, followed 
by redtop in the fall and alsike clover in the spring ; this, on account 
of failure, was replaced by corn in 191 5. At the last cultivation of 
the corn, grass and clovers were again sown, to be harvested for hay 
in 1916. 

On plat 2, lime was used more liberally and corn planted in 1913, 
in which grasses were seeded, supplemented by a seeding with clover 
the next spring. Hay .was harvested each year until the turf was 
turned under in the autumn of 1916 in preparation for the potatoes 
in 1917. 

1 Contribution 269 from the Agricultural Experiment Station of the Rhode 
Island State College, Kingston. R. I. Received for publication April 25, 1920. 

2 The senior author is director and agronomist and the junior author is 
assistant in field experiments, Rhode Island Agricultural Experiment Station. 



38 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Plat 3 was left in an acid condition and differed from plat I prin- 
cipally by having soybeans instead of lupine in 191 3, and by the fact 
that rye was used in the fall of 191 4. The grass seeding persisted in 
this case so that corn was not planted as on plat 1. 

Plat 4 was plowed in 191 3 the same as the other plats, but was 
then seeded to redtop without ever being fertilized or limed. What 
little grass grew each year was cut and left to decay so that the plat 
might remain practically in its original condition till prepared for the 
potatoes of 191 7. 

Plats 5 and 6 were both planted to corn in 191 3, in which were 
sown alfalfa on plat 5, and sweet clover and winter vetch on plat 6. 
The legumes were plowed in for green manures in 1914 before seed- 
ing to grasses and clovers for producing hay in 191 5 and 1916. 

The influence of the various treatments on the potatoes grown in 
1917 on the different plats was so slight that it may be considered as 
fairly within the limits of experimental error. The total yields of 
potatoes of the Green Mountain type in bushels per acre were as fol- 
lows : plat 1, 276 ; plat>2, 274 ; plat 3, 289 ; plat 4, 272 ; plat 5, 290 ; plat 
6, 274. The satisfactory rainfall, the uniform application per acre of 
60 pounds of nitrogen, 130 pounds of phosphoric oxid, and 50 pounds 
of potassium oxid, together with the fact that potatoes are not sensi- 
tive to differences in soil acidity, had left insufficient opportunity for 
the variations in previous treatments to exert a pronounced effect on 
potatoes. Therefore, the description of the details of the previous 
lime and fertilizer treatments may be considered first in connection 
with the winter wheat in 1918. This crop was considerably influ- 
enced, as may be seen by the following yields per acre: 

Grain, including many un- 



I'lat. thrashed heads, lbs. Straw, tbs. 

1 404 1,232 

2 832 2,328 

3 548 2,128 

4 456 1,664 

5 1,052 2,748 

6 1,128 3,152 



Mo advantage ( but possibly SOtne disadvantage, resulted to the 
wheat coincident with the attempt on plat 1 to introduce organic 

ittCf by green manure crops capable of growing on the soil in its 
-our condition. Comparison should he made w ith plat 4, which in the 
preliminary period served as a check plat. A portion of plat 1 which 
had received a small amount of lime produced a somewhat better 
yield Of wheat than the remainder of the plat which remained unbilled. 



HARTWELL & DAMON : IMPROVING A LIGHT SOIL. 



39 



Plat 2, as distinguished from plat I, had received sufficient lime for 
wheat, and the beneficial effect of the liming is shown plainly in the 
yield. From supplementary tests it appears improbable that the in- 
creased yield was due to a somewhat larger amount of fertilizer 
added to plat 2 than to plat 1 or 3. The small increase in yield on plat 
3 may be attributable to the presence of the lime in the Thomas slag 
phosphate which was used in 19 13 and 1914 to supply 80 pounds of 
phosphoric oxid, whereas acid phosphate was used on plat 1. 

Plats 5 and 6, which produced much the largest amount of wheat, 
were fertilized and limed alike during the entire experiment. Each 
received 3,000 pounds of hydrated lime per acre in 191 3 and a ton of 
ground limestone in 1914; whereas plat 2 received altogether only 
2,250 pounds of limestone per acre. As plats 5 and 6 received no 
more, fertilizer than plat 2, it is probable that the extra lime was the 
cause of the larger yields. 

The only difference between plats 5 and 6 was that in 191 3 alfalfa 
was seeded in the corn on the former, and a mixture of sweet clover 
and vetch on the latter. On August 3, 1914, when the crops were 
plowed under, the alfalfa was scattering and about a foot tall. The 
sweet clover was about 3 feet tall, and the total weight of green ma- 
terial on this plat, no vetch having wintered, was twice that on the 
alfalfa plat, or about 6 tons per acre. 

Both plats were seeded down to grasses and clovers in the autumn 
of 1914, and the following year, after being topdressed at the rate of 
30 pounds of nitrogen in nitrate of soda, 50 pounds of phosphoric 
oxid in acid phosphate, and 40 pounds of potassium oxid in muriate 
of potash, yielded hay as follows : plat 5, 3.1 tons per acre ; plat 6, 2.6 
tons per acre. 

In 1916, hay was harvested not only from these plats, but from 
plats 1, 2, and 3. The yields in tons of hay per acre are assembled 
for comparison: Plat 1, 3.9; plat 2, 3.0; plat 3, 3.0; plat 4 (check), 
very little ; plat 5, 3.4 ; plat 6, 3.6. 

Each plat had been topdressed that year at the rate of 300 pounds 
of common salt and 386 pounds of acid phosphate. Plats 1 and 3 
received 30 pounds of nitrogen, plat 2, 40 pounds, and plats 5 and 6, 
50 pounds each, all in nitrate of soda. It was estimated that on the 
very acid plats 1 and 3 about nine tenths of the grass was redtop, the 
remainder being mostly timothy ; whereas on plat 2, which had re- 
ceived 2,250 pounds of limestone in 191 3. the reverse was true. 3 

3 This plat produced per acre in 1913 22 bushels hard corn. 21 bushels soft 
corn, and i.iq tons stover; in 1914 1.88 tons hay: and in 1915 2.19 tons hay; 
with the total addition for the three years of 100 pounds nitrogen, 150 pounds 
of prosphoric oxid, and 120 pounds potassium oxid. 



40 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

It was ascertained from samples that, in 1913, 4,150 pounds per 
acre of green lupine containing 18.7 pounds of nitrogen were plowed 
in on plat i, and 8,973 pounds of green soybe^is^sontaining 56.5 
pounds of nitrogen were turned under on plarr2r~" 

Altho it had been decided to depend upon the potato crop of 191 7 to 
demonstrate some of the effects of the different treatments of the 
plats, it was realized that the tolerance of this crop for soil acidity un- 
fitted it to show the effect of liming. It was thought probable, how- 
ever, that soil so light, and ■ in its original condition so devoid of 
humus, would some time during the summer be sufficiently lacking in 
moisture so that the moisture-conserving effect of the green manures 
added to certain plats would be demonstrated by the potato yields. 
Consequently, the potatoes were fertilized liberally on all plats in 
order that the organic matter might be the influencing factor if the 
season was dry. 

As so often happens, however, under the uncontrollable conditions 
in the field, the very circumstances in which the demonstration might 
be expected to prove successful did not exist. The season was a wet 
one. and the potatoes yielded as much on the control plat as on any 
which had received considerable increment of humus from the green 
manures. Not only was the temperature of April and May below 
the normal for those months, but the rainfall was liberal during the 
time of most rapid growth, as shown by the following: April, 3.01 
in.; May, 5.48 in.; June, 5.25 in.; July 1. 71 in.; August, 2.85 in. 

In our generally humid climate, it might take many years to demon- 
strate, under field conditions, the accepted moisture-conserving value 
of humus, and it is not a surprise that this was not done during the 
limited time of this experiment. 

( >ne would scarcely have predicted, however, that even with the 
liberal rainfall and fertilizer, the control plat would produce 272 
bushels of potatoes. In case of this plat, the light, unproductive pas- 
ture -oil was simply plowed and seeded to redtop in 1 < j 1 3 , after which 
nothing was added nor removed until it was plowed again in the fall 
of [916 and fertilized in the Spring of i<)i7 in preparation for 
potatoes. 

Winter wheat, which wa- grown after the potatoes, is sufficiently 
sensitive to acidity so that the liming on certain plats appeared to be 

at least the principal factor influencing its growth. The rainfall in 

'lie spring of \<)\K during the months when it would he most useful 
to the wheat was as follows; March, 2.72 i April, 5.60 in.; May, 
2.29 in.; June, j. 71 in. With such a liberal rainfall, it could scarcely 



GARBER ! 



RUST RESISTANCE IN OATS. 



41 



be expected that a possible increase in moisture conservation by addi- 
tional humus would have any effect on the crop. 

The very pronounced influence of the liming, whenever a crop was 
grown which is sensitive to soil acidity, shows that the first consid- 
eration should be given to this process in connection with attempts 
to increase crop production on such soils. Of the fertilizer elements, 
phosphorus would probably be used most economically, while legumes 
should prove beneficial in the long run, not only for collecting nitro- 
gen but for increasing the humus. 

A PRELIMINARY NOTE ON THE INHERITANCE OF RUST 
RESISTANCE IN OATS. 1 

R. J. Garber. 2 

Breeding for rust resistance in wheat has been carried on rather 
extensively, but in oats little has been done. Parker has made a vari- 
etal survey 3 of oats with respect to rust reaction and also reported 4 on 
the behavior in the F 2 of a cross between parents differing in their 
reaction toward crown rust (Puccin'a lolii avenae). In this cross 
susceptibility to crown rust was inherited as a dominant character. 

During the summer of 191 8, crosses 5 were made between a selec- 
tion of White Russian oats {Avena sativa orientalis) resistant to 
stem rust (Puccinia graminis avenae)' and a selection from each of 
the two highest yielding varieties grown at University Farm. These 
varieties, Minota and Victory (both Avena sativa), are very suscep- 
tible to stem rust. 

The F x plants were grown in the greenhouse the winter after the 
crosses were made and a limited number matured soon enough to 
permit growing a small F 2 generation the following summer. Ma- 

1 Published with the approval of the Director as Paper No. 215, of the 
Journal Series of the Minnesota Agricultural Experiment Station, University 
Farm, St. Paul, Minn. Received for publication August 23, 1920. 

2 Formerly assistant in plant breeding, Minnesota Agricultural Experiment 
Station. 

3 Parker, J. H. Greenhouse experiments on the rust resistance of oat varie- 
ties. U. S. Dept. Agr. Bui. 629, 16 p. 1918. 

- Parker, J. H. A preliminary study of the inheritance of rust resistance in 
oats. In Jour. Amer. Soc. Agon., 12 : 23-38. 1920. 

5 These crosses were suggested and the parental material furnished by H. 
K. Hayes, Head of the Section of Plant Breeding, Division of Agronomy and 
Farm Management, University of Minnesota. 



42 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



tured seed from three different F, plants of the cross, Minota X 
White Russian, and from a single plant of the cross, White Rus- 
sian X Victory, were sown in the nursery in a manner to permit in- 




Fi<.. i. Culms of suscc|)i il,lc and resistant oats. From to]) to bottom, in 

Roup of three: Susceptible Victory parent; susceptible plant of F s of White 
KMIiian X Victory; resistant' plant of F 2 of White Russian X Victory ; re- 
sistant White- Kn ian parent. N'otc normally developed nredinia on the Vic- 
tory plant and on one of the F, plants. 



dividual plant study. En all there were 1.42 F| plants of the former 

and 1 1 F plant- of the latter. The parents were sown simi- 
larly in rows beside those of the F, plants. The K 2 plants and their 



garber: rust resistance in oats. 



43 



parents were sown about two weeks after the rest of the oat nursery. 
The summer of 1919 proved to be favorable to the development of 
stem rust and a heavy natural epidemic occurred. In addition, rust 
spores were artificialy applied to the parents and F 2 plants. Owing 
to the lateness of seeding, both the progeny and parents were especially 
subjected to the attack of rust. Under the above conditions, the sus- 
ceptible parents became heavily rusted whereas none or very few 
small uredinia developed on the resistant White Russian variety. 

The F 2 plants showed sharp segregation and were placed in two 
classes, those similar to the susceptible parents and those similar to 
the resistant parent (see fig. 1). Eliminating three plants of some- 
what doubtful classification the results obtained in F 2 were as follows : 
Minota X White Russian, 104 resistant, 36 susceptible 
White Russian X Victory, 31 resistant, 9 susceptible. 

Here is evidence of a single hereditary factor difference with re- 
spect to the rust reaction of the host plants used as parents. Re- . 
sistance apparently behaves as a dominant character in these crosses. 

AGRONOMIC AFFAIRS. 
THE SOCIETY IN 1921. 

The American Society of Agronomy has just passed thru a hard 
year. With no appreciable change in total membership, there was 
a marked increase in printing costs, which necessitated the curtail- 
ment of the Journal in recent months. The unrest following the 
war has seemed to make it difficult for us to hold old members and to 
get new ones. The annual meeting of the Society at Springfield, 
Mass., in October, however, was the most successful ever held, and 
it is believed marked a milestone in our progress. The development 
of the symposium idea in the programs has greatly stimulated interest 
in the meetings and the publication of the resulting papers should add 
greatly to the value of the Journal. In the February issue the six 
papers presented at Springfield on the teaching of crops and soils 
will be printed, and these will be followed by the lime papers. Later, 
the corn improvement papers from the special program meeting 
held at Chicago on December 31 will appear. These with other 
special articles should make up a very interesting volume for 192 1. 
The only question now is, will the Society have sufficient funds to 
print all the worth-while papers? 

Two ways out of the financial difficulty facing the Society were 



44 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



suggested at Springfield, increasing the annual dues and increasing 
the membership. A slight increase in the annual dues (from $2.50 
to $3.00) was voted, and plans for a vigorous campaign for members 
were discussed. That this campaign is gofn^forward successfully 
in some sections is evident from the number of new members added 
recently. It is hoped that this is but an earnest of what is to come, 
for of the 77 new names 54 are from three States, 24 from Iowa, 
18 from Texas, and 12 from Kansas. With 45 States yet to hear 
from, there is room for abundant further growth. Which State 
will head the list a month from now? Texas now leads in total 
members, with 42 ; Kansas is a close second with 38. 

Do agronomists hold their profession too cheaply ? Why is it that 
the American Chemical Society, with dues of $10 a year, has several 
thousand members, while the American Society of Agronomy 
struggles along with a few hundred members at $2.50? At the last 
annual meeting of the chemists it was shown that the $10 dues were 
not sufficient to meet the needs of the Society, and the amount was 
raised to Si 5! Surely agronomists ought to take sufficient pride in 
their profession to support their own Society, when the cost is so 
small. Let's set the mark this year at i,oco members, and then see 
how far we can go past it! 

BOOK REVIEW. 

Son. Alkali: Its Origin, Nature and Treatment. By F. S. 
I funis. 258 p., ill us. New York, John Wiley and Sons, J()20. — To 
one who has even a superficial knowledge of the soil resources of the 
western Tinted States, especially thai part of the country lying west 
of the continental divide, the importance of the alkali problem is 
clearly apparent. W hen one realizes that this country contains only 
a minor portion of the alkali lands of the world, the importance of 
the problems involved in securing a satisfactory utilization of these 

lands is profoundly impressive. The challenge of the alkali problem 

has |»« < ■ ■<!>!' <1 b\ a large number of investigators. Chemists, 
agronomists, botanists, engineers, economists, and other specialists 
have attacked it with varying degrees of ability .and persistence, and 
with varying productiveness. None of lliem lias solved it, but each 
ha left bis contribution, large or Small, Eor whatever use the world 
Can make of it. The aggregate value of these contributions is very 
great. In bringing together in one small volume brief summaries, 



AGRONOMIC AFFAIRS. 



45 



showing many of the outstanding features of the contributions made 
to the literature of soil alkali by no fewer than 180 investigators, Dr. 
Harris has rendered a distinct service. 

The book should be useful, with its short chapters in which a large 
number of the commonly considered aspects of the subject are briefly 
discussed in simple language, and with its extensive bibliography. 

The author makes a high estimate of the aggregate area of alkali 
lands, and devotes to their geographic distribution a chapter which 
would be improved by the use of a good map and of more definite 
statistics, if they were available, as they probably are not. He then 
discusses the origin of alkali, placing special emphasis on the geologic 
factors ; the nature of alkali injury to plants ; toxic limits, which, by 
the way, are very imperfectly understood ; indicator vegetation ; 
methods of making alkali determinations ; Equilibrium and antago- 
nism among alkali salts ; the relation to alkali to physical and biological 
conditions in the soil ; the movement of soluble salts in the soil ; 
methods of reclaiming alkali lands, with a separate chapter on drain- 
age ; crops for alkali lands ; alkaline water for irrigation ; and methods 
of judging alkali lands. He quotes freely from Hilgard, Cameron, 
Kearney, Briggs, and other investigators, and from publications by 
himself and his associates. 

In reading the book one is impressed with the large number of 
essential points which need further investigation. The author alludes 
repeatedly to this need, and by the very frequent use of the verbs 
" may " and " might," indicates perhaps how keenly he feels it. The 
alkali question has many complexities' and ramifications, and our 
facilities for investigating it are very inadequate. In writing a text- 
book on the subject, a conscientious author probably experiences fre- 
quently a conflict between his desire to be constructively informative 
and his anxiety to avoid making ill-founded statements. 

The problems involved in the utilization of alkali lands, even 
more perhaps than those which are encountered in the reclamation 
of some of our most sandy areas, require of the student more than 
usual patience, persistence, ingenuity, and intelligent optimism. These 
problems are a persistent challenge. Their complete solution would be 
of immeasurable benefit. It would make available for large popula- 
tions vast regions of territory admirably located and favored with the 
most delightful climates. It is regrettable that we do not have a 
sufficient number of men with the necessary training, temperament, 
and opportunity to attack the problem on. a thoroly comprehensive 
scale and, if need be, on a life-long basis. — F. D. F. 



46 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



MEMBERSHIP CHANGES. 

It is a pleasure to report that since copy for the last issue went to 
press the largest number of new members ever reported in a like 
period has been received. Unfortunately, however, at this time the 
members whose dues for 1920 have not been paid and whose member- 
ships have therefore lapsed must also be reported. This number 
slightly exceeds the additions, so that a slight net loss is shown. It is 
entirely probable, however, that some of those now listed as lapsed 
will arrange for their reinstatement later, so that the Society is now 
in a position to go forward, new members added to the list after this 
time being a distinct gain. The membership reported in the last issue 
was 556, since which time 77 new members have been added, 1 mem- 
ber has resigned, and 81 have been dropped for nonpayment of 1920 
dues, making a net loss of 5 and a present membership of 551. In 
order to save space, names and addresses of new members, names of 
resigned and lapsed members, changes of address, and other member- 
ship changes will no longer be printed in the Journal. Members are 
urged to report changes of address or failure to receive the Journal 
to the Secretary or the Editor. Every effort is made to keep the 
mailing list complete and correct, but members must cooperate in this 
undertaking. 

NOTES AND NEWS. 

Mark A. Carleton, formerly cerealist of the Federal Department 
of Agriculture, is now plant pathologist for the United Fruit Com- 
pany, with headquarters at Bocas del Toro, Panama. 

H. K. ( ates, formerly agronomist in charge of weed investigation 
in the Department of Agriculture, resigned August 15 to accept a 
position in the crop insurance department of the Hartford Fire ln- 

rarance Co., with headquarters at Atlanta, Ga. 

G. C. ( reelman, for many years president of the Ontario Agricul- 
tural College, has resigned to become agent-general for Ontario in 
London, the business of his office being largely the direction of the 
tiofl of prospective immigrants to Ontario's agricultural oppor- 
tunities. II,- l i;i s been -u e.eded at (iuclph by J. 15. Reynolds, for- 
mer!) president of the Manitoba Agricultural College. 

OO (Vomer, formerly assistant in farm crops at the Purdue 
Untversif) Itation, has resigned i,, engage in farming at Dale- 

ville, bid. 



AGRONOMIC AFFAIRS. 



47 



E. P. Deatrick is now connected with the department of soil tech- 
nology in the Cornell University college of agriculture. 

Geary Eppley is now assistant in agronomy and J. R. Haag is as- 
sistant in soils at the Maryland college and station. 

Thomas F. Hunt, dean of the college of agriculture of the Uni- 
versity of California, now on a year's leave of absence in England, 
has been appointed delegate to represent the United States at the 
International Institute of Agriculture at Rome. 

W. D. Hurd is now director of the Soil Improvement Committee of 
the National Fertilizer Association. On October i this committee 
established headquarters in Washington, D. C, with offices in the 
Southern Building. 

Ralph E. Johnston is now extension agronomist in South Dakota. 

Dr. David Kinley, professor of economics and dean of the graduate 
school of the University of Illinois, has been elected president of that 
institution. 

Dr. Ernest H. Lindley, for the past three years president of the 
University of Idaho, is now chancellor of the University of Kansas. 

Henry F. Murphy is now assistant in agronomy at the Oklahoma 
college and station. 

J. C. Overpeck is now assistant professor of agronomy in the Uni- 
versity of Wyoming and assistant agronomist of the station. 

P. H. Ross, formerly State leader of county agents in Missouri, is 
now director of extension in that State, succeeding A. J.- Meyer, who 
resigned to become executive secretary of the Missouri State Farm 
Bureau. 

Nelson S. Smith, formerly a member of the faculty of the agri- 
cultural school at Claresholm, Alberta, is now engaged in farming 
at Olds, Alta. 

Rupert L. Stewart, formerly agronomist of the New Mexico col- 
lege and station, now has charge of the Smith-Hughes agricultural 
teaching in the Pomona, CaL, high school. 

E. P. Taylor, formerly director of extension in Arizona, is now 
with the fertilizer department of the Anaconda Copper Mining Com- 
pany, with headquarters at Chicago, 111. He has been succeeded as 
director of extension by W. M. Cook. 



48 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



C. M. Woodworth, for the past several years engaged in flax- 
disease studies for the Federal Department of Agriculture in coopera- 
tion with the Wisconsin station, is now engaged in plant-breeding 
investigations with the department of agronomy of the Illinois college 
and station. 

H. L. Shantz returned to Washington, D. C, early in September, 
after more than a year of agricultural exploration in Africa for the 
United States Department of Agriculture, during which time he 
crossed Africa from the Cape to Cairo and made many side trips to 
little-known districts. He has now been placed in charge of the 
physiological and fermentation investigations of the Bureau of Plant 
Industry. 

INTERNATIONAL CROP IMPROVEMENT ASSOCIATION. 

The second annual meeting of the International Crop Improvement 
Association, a federation of the State and Canadian crop improve- 
ment and experimental associations, was held at the Stock Yards Inn, 
Chicago, on December i, 1920, in connection with the International 
Grain and Hay Show. The general topic for discussion was " Seed 
Inspection, Certification, and Marketing." The following program 
was presented : 

1 ( "anada's Method, by L. H. Newman, Secretary Canadian Seed Growers' 
Association. Ottawa, Out. 

2. Opinions from Indiana's Experience, by W. A. Ostrander, Indiana Corn 
Growers' Association, LaFayette, Ind. 

3. Michigan's Inspection and Marketing System, hy A. L. Bihbins, Secretary 
Michigan Crop Improvement Association, East Lansing, Mich. 

.4. Alfalfa Seed Inspection in Idaho, by B. F. Sheehan, Secretary Idaho Seed 
Growers' Association, Boise, Idaho. 

- Grimm Alfalfa Seed Inspection, by W. R. Porter, Secretary Grimm Alfalfa 
Producers' Association, Fargo, N. Dak. 

At the conclusion of the program, the following officers were 

drcted for the ensuing year: 
President, G. H. Cutler, University of Alberta, Edmonton, Alta. 

! t Via President, R. A. Moore, University of Wisconsin, Madison, Wis. 
Second Vice-President, B. F. Sheehan, State Seed Commissioner, Boise, 
Idaho 

'I hird Vm 1 I'm ident, \ I I'.ilihins, Mich. Agr. Odlegc, Kast Lansing, Mich. 

fteasurcr, .1 \V. Xirolson, Michigan Kami Knrcan, Kast Lansing, 

Mich. 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. February, 1921. No. 2 

PREREQUISITES FOR AGRONOMY SUBJECTS. 1 

L. E. Call. 

The subject assigned to me on the program is too broad in one 
direction properly to state the material that I wish to present this 
afternoon, and too narrow in another direction. With your permis- 
sion I will confine my paper to a discussion of prerequisites for farm 
crops subjects and especially those that are required of all agricultural 
students in most educational institutions. On the other hand, I wish 
to broaden the scope of my paper to include a discussion of the place 
in the curriculum where the required work in farm crops should be 
given. 

A year ago this fall at the annual meeting of this Society a few 
minutes were used to discuss the subject of farm crops teaching. At 
that time there seemed to be a great difference of opinion as to 
whether the required work in farm crops should be offered in the 
freshman, sophomore, or junior year. There was also a difference 
of opinion as to the desirability of requiring any training in the 
sciences as a prerequisite for the work in crops. 

Since that time I have had an opportunity to study the curricula as 
given in the most recent catalogs of a number of the leading agricul- 
tural colleges and universities of this country. In all, the courses of 
study of twenty-five of the leading institutions offering work in 
agriculture were compared. Of these institutions nine give their 
required work in farm crops in the freshman year; two other institu- 

1 Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 18, 1920. 

2 Professor of Agronomy, Kansas State Agricultural College, Manhattan, 
Kans. 



49 



50 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



tions offer brief courses in the freshman year called " Crop Produc- 
tion " or "Agronomy." These courses in both cases are a part of 
the year's work in agriculture made up of work offered by the de- 
partments of animal husbandry, dairy husbandry, horticulture, and 
agronomy. In both instances these institutions give other required 
work in farm crops that is taught in the junior year after the student 
has received some training in botany. Seven institutions offer their 
required work in the sophomore year, six in the junior year, while 
three institutions, whose courses are largely elective, do not require 
any farm crops work of all agricultural students. All of the institu- 
tions which offer the required courses in farm crops in the sopho- 
more or junior years require general botany as a prerequisite for 
crops. Some of them mention chemistry specifically as a prerequisite, 
and two institutions that offer the farm crops work in the junior year 
require soils as a prerequisite. One institution that offers farm 
crops in the freshman year mentions the fact that general botany 
must accompany or precede the work in this subject. Of the twenty- 
five institutions whose courses of study were investigated, sixteen 
recognize the value of botany as a prerequisite for farm crops, and a 
few others specifically mention chemistry and soils. 

It appears from this study of curricula that the leading institutions 
requiring work in farm crops can be grouped into three classes in 
respect to the requirement of prerequisites for this subject. First, 
those that require no prerequisite and offer farm crops in the fresh* 
man year; second, those that require general botany as a prerequisite 
and offer the work in the sophomore or junior year; and third, those 
that require general botany and soils as prerequisites and offer the 
work in the junior year. There are probably advantages and dis- 
advantages that can be mentioned for each of these arrangements. 
Perhaps no one of them will answer the requirements at every institu- 
tion in the United States, but it would certainly seem that it would 
be possible to have a greater uniformity among our institutions than 
now exists in both the prerequisites required for farm crops and as 
to the year in the curriculum thai the course is offered. Probably few 
other required subjects in the agricultural course have been "wiggled 

and wobbled" around like the courses in farm crops. 

Those institutions that offer farm crops in the freshman year and 

require no prerequisite for the course generally admit that it would 
be desirable to have general botany preceding the work in crops, but 

m order to accomplish t hi ^ it would he necessary to postpone the work 
in <-<<i. until the sophomore yen. In so doing they lose the sup- 



call: prerequisites for agronomy subjects. 51 

posed advantage of, first, using farm crops in the freshman year as 
a means of holding the interest of the student in agriculture or, in 
other words, using it as a sugar coating to the bitter dose of science 
that the student is required to swallow; and second, using the subject 
as a means of meeting the agricultural students in the freshman year 
and in that way interesting them in farm crops with the hope that 
they may later specialize in this phase of agriculture. Let us use a 
few moments to consider the first reason for offering farm crops in 
the freshman year, that is, as a means of holding the student's interest 
in agriculture. First, is it necessary to offer agricultural work during 
the freshman year in order to hold the student's interest, and second, 
if it is necessary to do so, is farm crops the subject that should be 
used for this purpose? 

There is a difference of opinion among different educators as to the 
desirability of offering any strictly agricultural work during the 
freshman year. Some think that the entire year should be used to 
give the student the training in English and the sciences which he will 
need later for his work in agriculture. Most educators who have 
studied the question believe that while it is desirable to devote as 
much time as possible to the sciences during the freshman year that 
at least a small amount of practical or applied agricultural work 
should be given during this period. If we admit- this to be desirable, 
should farm crops be the course used for the purpose? I think not. 
There are other lines of agricultural work in which freshman agri- 
cultural students as a class are more interested, and which can be 
taught satisfactorily without previous training in science. I refer to 
work in animal husbandry, such as stock judging and the study of 
market types and classes and breeding types and classes of live stock. 
This is a type of work that can be taught almost as satisfactorily to 
freshmen as to upper classmen because proficiency in the work is 
secured by practice and not by a study of the scientific principles 
underlying the work. It is a relief from the more detailed work over 
the microscope in botany or zoology and the extremely accurate work 
in chemistry or physics, and above all is work in which the average 
agricultural student is very much interested. A poll of the fresh- 
man class at our institution this fall showed that out of 175 students, 
94 were especially interested and expected to major in animal hus- 
bandry, 20 in dairy husbandry, 18 in agronomy, 4 in horticulture, 4 in 
agricultural economics and farm management, while 35 were un- 
decided as to the subject in which they would specialize. From the 
standpoint of student interest, animal husbandry would undoubtedly 



5^ 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



be the best subject to offer at our institution during the freshman 
year, and a course in judging live stock is given to all freshmen in 
agriculture here. 

Of what value is the second reason that is often advanced for 
requiring farm crops in the freshman year, namely, that it will in- 
terest students in the subject and in that way increase the number 
that may later specialize in the work ? Perhaps to a certain extent it 
will serve this purpose, but can we afford to weaken the required 
course in farm crops for all agricultural students in order that a few 
may be induced to specialize in the work? Personally I think the 
course is weakened when taught in the freshman year without gen- 
eral botany as a prerequisite and that it should not be weakened for 
the majority for any supposed benefit that may be derived by the 
few who will later specialize in farm crops. The curricula in our 
engineering colleges are not arranged to permit each department of 
engineering to meet the men in the freshman year, neither do our 
medical colleges think it desirable to require obstetrics or pathology 
of the freshman students in order that more of them may specialize 
in these subjects later in their course. In the best engineering, 
medical and other technical schools, the courses are outlined to give 
the student as quickly as possible the necessary training in the sci- 
ences and to delay the technical work until the student is properly 
prepared for it. This should be our aim in agriculture. 

\\ here for any reason it is thought wise to permit each agricul- 
tural department to offer some work in the freshman year in their 
respective fields, would not the best solution be a combined course 
in general agriculture for freshmen such as is offered by the Massa- 
chusetts Agricultural College, in which each department offers a 
certain portion of the work? Under this arrangement the students 
would all meet an instructor in farm crops and obtain an insight into 
the work, but would not obtain their real training in the subject until 
later in the course alter they had taken the proper foundation courses 
in botany. It has always seemed to me, however, that a general 
com-' of this kind was a tremendous waste of time in view of the 
man other things that il would be desirable to have the student take, 
but which are crowded nut became of lack of time. We have 
eliminated all com of this kind ;i t our institution but we give the 
student- lOffie lieljj in vocational guidance bv means of a series of 
Weekly lecture! during the first semester of the freshman year, given 

by the President, the deani of agriculture and extension, and the 



wentz : 



STANDARDIZING CROPS COURSES. 



53 



heads of different departments in which the student may later take 
his major work. 

Let us now consider the institutions that offer the required work 
in farm crops in the junior year. They are of two classes. First, 
those that do not offer general botany until the sophomore year and 
thus the work in crops is not given until after the student has had 
his botany; and second, those that require soils as a prerequisite for 
farm crops. I believe that nearly every one will agree that it would 
be desirable for the student to have a knowledge of soils before 
taking crops, but it is questionable if it is of sufficient importance to 
justify delaying the crops work until the junior year. Students in 
animal and dairy husbandry should have farm crops before taking 
Principles of Feeding, and it is certainly desirable to allow two years 
for elective work in farm crops for those students who expect to 
major in those subjects. It would seem to me, therefore, that for the 
best interests of all students the course in farm crops should be 
offered in the sophomore year and that general botany and chem- 
istry should be required as prerequisites. If this is done, the depart- 
ment offering instruction in farm crops should have something to 
say regarding the type of work required of the agricultural students 
in botany. Too often the freshman students of agriculture are 
placed in the same botany classes with students from other colleges or 
departments and given work that may be desirable for a student that 
expects to major in botany, or perhaps pharmacy, but that is of much 
less value to the agricultural student. If the classes in botany are 
properly divided and the courses are planned along the lines of 
student interest, and if the right kind of botany is taught, it will 
furnish the proper foundation for the work in farm crops and 
should be required as a prerequisite for this subject. 

THE STANDARDIZATION OF COURSES IN FIELD CROPS. 1 

John B. Wentz. 2 

In the last few years we have heard a great deal about the standard- 
ization of work in our educational institutions. There has been a 
tendency toward more uniform standards of requirements for en- 
trance and for the amount and type of work required of students 

1 Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 18, 1920. 

2 Professor of Agronomy, Maryland State University, College Park, Md. 



54 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



after entering the college or university. In years past it was common 
to look to certain outstanding colleges for high standards in certain 
phases of work. For instance, if one thought of studying animal 
husbandry there were one or two institutions in the country which 
stood out far above the others in work offered in this subject. If 
soils was the subject in mind probably it would be some other institu- 
tion or if it was field crops probably another institution. This tend- 
ency to look to certain institutions as being the standards in particular 
phases of work probably always will exist, but at present there seems 
to be more of an effort to standardize the work in a certain subject 
in the various colleges of the country. In the fundamental sciences 
such a? chemistry, physics, botany, and zoology we find that the 
undergraduate courses have been fairly well standardized. That is, 
we have freshman courses in chemistry which are pretty much the 
same in all of our State colleges and we have the freshman course in 
botany common to most of the colleges. These courses are offered 
in the same year and have very similar content. If a student tells 
you he has had freshman chemistry, you know about what chemistry 
he has had. 

In some lines of agricultural work there has been considerable dis- 
cussion on teaching methods and courses, and their content and 
objectives. The Association of American Agricultural Colleges and 
Experiment Stations has had a committee working along this line and 
in the reports of this committee are found some suggestions as to 
Standardization of work in field crops as well as other agricultural 
subjects. The Society for Horticultural Science has for several 
years had a committee on courses of study. This committee has 
made reports to the Society which no doubt have had great influence 
in the standardization of courses in horticulture. Last June there 
;t- a r< in ference at Lexington, Ky., of those interested in teaching 
to make ;i study of what should be the nature of the beginning 
course in soils. 

There arc al least three different phases of this subject of standard- 
ization oi course material which may he considered. The first of 

tlx - , and the one which is introduced in this paper, is the uniformity 
of work offered by similar institutions; second, the division of sub- 
ject matter between the departments of a single institution; and third, 
the division of subject matter into courses within a department so 
as to prevent duplication of material. The first of these phases of 
the lubjed if the most general in that it affects all the institutions 
in a common way. It is the phase of the subject which requires an 



WENTZ I STANDARDIZING CROPS COURSES. 



55 



exchange of ideas between institutions and probably is the most 
logical point of attack in standardization, altho there will necessarily 
be some consideration, within institutions, of the other questions 
before this one can be properly disposed of. The proper division of 
subject matter between departments will be arranged within indi- 
vidual institutions but if anything standard is adopted as to the 
courses and their content in a certain subject the country over it 
must be done by the exchange of ideas between departments handling 
this work in the various institutions. 

How far we can go in standardizing our agricultural courses may 
be questioned but we will all agree that a great deal could profitably 
be done in this direction. It would not be possible or even desirable 
for a group of authorities on field crops to get together and make up 
a definite list of courses and specify the content of these courses, the 
number of hours that shall be devoted to each course, and the year 
of the college curriculum in which they should be placed and say that- 
each field crops department of the country should adopt this standard 
list of courses. This would be impossible because of the difference 
in crops grown in various States and the difference in types of farm- 
ing. However, it seems that certain courses in field crops could be 
considered standard courses, at least for certain large sections of the 
country, and the content of these courses could be more or less 
standard. 

One who has had the responsibility of organizing and carrying out 
or supervising teaching in field crops and who has given special 
attention to this phase of agronomic work realizes that there are 
numerous problems to be met. Some of these problems are common 
to other agricultural teaching or even to all teaching, while others 
apply especially to the subject of field crops. It is not the purpose 
of this paper to list these problems and suggest solutions, but merely 
to present a brief survey of course material in field crops now offered 
by the agricultural colleges of the country with a view to encourag- 
ing some thought on the question of standardization. 

To get something definite in the way of a survey of present condi- 
tions a careful study was made of the catalog descriptions of courses 
now offered in field crops by the agricultural colleges. In most cases 
these descriptions were complete enough so that it was possible to 
get a fairly good conception of the subject matter covered by each 
of the named courses. A list was made of all the courses found ; 
then, after studying the descriptions of these courses as they ap- 
peared in the various catalogs, they were classified under standard 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



names according to subject matter covered. The next question that 
was taken up was the year of the college curriculum in which these 
courses are placed. After the courses had been classified on subject 
matter it was determined from the catalogs what year each of these 
courses is offered by the different colleges and the number of credit 
hours set aside for each course. 

After listing all the different names of courses it was found that 
there are now being offered in the United States 133 differently 
named courses in field crops. The average number of courses 
offered by a single college is 6 and a fraction, the maximum 21, and 
the minimum 2. By classifying these courses as far as possible on 
subject matter or content this number was reduced to 47. In Table 
1 will be found names of courses which are offered by not less than 
three colleges, together with the number of colleges by which each 
course is offered. The course names in this table are the standard 
names assumed in classifying the courses as they appeared in the 
catalogs* arranged in order of the number of colleges by which they 
are offered. It probably would be possible further to reduce this 
number of standard courses by combining some of the courses as 
they have been listed in the table. For instance, there may be some 
different division or combination of the judging and grading work. 
However, in making up this list of standard names an attempt was 
made to classify the courses exactly on ground covered as described 
in the catalogs without leaving out any divisions or combinations of 
subject matter or making any new divisions or combinations. 

Table i.— Courses offered by not less than three colleges, together with the 
number of colleges by which each course is offered. 

Forage Crops 36 Grain Judging 8 

Crop Breeding 30 Small Grains 6 

Field Crops, General 29 Cotton 6 

Cereal Crops 24 Crop Rotations 4 

Methods of Investigation 17 Weeds 4 

R< earch and Thesis 16 Judging and Grading Field Crops. 4 

Seminar 14 Grading Field Crops 3 

Special Crops 10 Grain Grading 3 

and Seed Testing 9 Special Problems in Crop Produc- 

Corn 8 tion 3 

Advanced Field Crops 8 

In Table 1 only 20 different courses appear, meaning that the re- 
maining 27 are offered by less than l luce colleges. This indicates 
rec after Classifying as far as possible the courses offered in 



WEXTZ : 



STANDARDIZING CROPS 



COURSES. 



57 



field crops, a large number of courses are- offered by only one or two 
colleges. In a few cases there may be justification for the offering 
of a course in a certain college different from any course offered by 
any other college, but cases like this, it would seem, should be very 
few. If you give any weight to the votes of the colleges as indicated 
in this table, it seems that almost any field crops department should 
be able to select its courses from among this list of 20. This would 
reduce the number of courses in field crops in the country from 
133 to 20. 

Table 2 shows in what years each of the 20 standard courses are 
offered in the college curricula. In some of the catalogs it was not 
possible to determine in what year some of the courses are offered. 
In cases where it was stated that a course could be taken in either 
one of two or three years the earliest year was recorded. 

Table 2. — Year in which field crops courses are offered in the college curricula. 



Number of colleges offering in — 



Name cf course. 


Freshman 


Sophomore 


Junior 


Senior 




year. 


year. 


year. 


year. 


Forage crops 


I 


12 


16 


5 


Crop breeding 






8 


17 


Field crops, general 


12 


9 


3 


3 


Cereal crops 


6 


4 


10 


1 


Methods of investigation 






2 


10 


Research and thesis 








14 


Seminar 






2 


13 


Special crops 






1 


3 


Seeds and seed testing 






3 


2 


Corn 


2 


1 


3 


2 


Advanced field crops 






1 


5 


Grain judging 


2 


2 




2 


Small grains 


I ■ 


2 


2 


1 


Cotton 






1 


5 


Crop rotations 








1 








1 




Judging and grading field crops 






1 


1 


Grading field crops 






1 


2 


Grain grading 






1 




Special problems in crop production 








2 



The outstanding thing in Table 2 is the irregularity in time at 
which some of the courses are offered. There are five courses out 
of the twenty which are offered in all the four years. It seems that 
there should be no reason why one college should offer cereal crops, 
for instance, in the freshman year and another college offer the same 
course in the senior year. 

The purpose of Table 3 is to show the number of credit hours 



5$ JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

devoted to the various courses by the agricultural colleges. In a few 
cases the number of hours was not given and these courses could 
not be represented in the table. In all cases the number of credit 
hours is on the basis of two semesters a year. Where the number 
of hours was given by terms in the catalogs they were reduced to 
semester credit hours and where fractions appeared the nearest whole 
number was used in the table. 

Table 3. — X umber of hours devoted to the various courses in field crops by 
the agricultural colleges. 



Number of colleges offering — 



Name of course. 


1 hour. 


2 hours. 


3 hours. 


4 hours. 


5 hours or 
more. 


Forage crops 


I 


8 


21 


2 


4 


Crop breeding 




13 


13 


2 


1 


Field crops, general 




4 


10 


6 


7 


Cereal crops 


I 


5 


14 


2 


1 


Methods of investigation 


3 


3 


4 


2 


1 






1 




6 


5 




9 


3 




1 






2 


3 


A 




1 




1 


7 


1 










6 


2 






Advanced field crops 






4 


1 


r 


Grain judging 


3 


4 


1 






Small grains 




3 


2 










4 


I 








2 


2 








Weeds 


1 


2 








Judging and grading fit-Id crops 


i 


2 








Grading field crops 




2 












1 








Special problems in crop production 






1 







A wide variation in the number of hours devoted to the various 
ill he in Med in Table 3. There may be some reason for this 
variation due to the difference in the relative importance of certain 
m different parts <»t the country but even here there probably 
COtlld be more uniformity. 

Summary. 

In general, there i^ a tendency on the pari of educational institu- 
tion- toward the standardization of work offered. 

How far we can go in the standardization of courses in agricul- 
tural lubjecti may be questioned but certainly all will agree that a 
great deal eonld well be done in this direction. 

At the present time tin re are listed in the catalogs of the agricul- 



SLATE : FIRST COURSE IN FIELD CROPS. 



59 



tural colleges of the United States 133 differently named courses in 
field crops. When these courses are classified according to ground 
covered the number is reduced to 47, and of these 47 only 20 are 
offered by more than one or two colleges. 

Almost any field crops department of the country should be able 
to select all its courses from among this comparatively small group 
of 20. 

Table 2 shows that there is great irregularity in the positions of the 
field crops courses in the college curricula. 

Table 3 shows great variation in the number of hours devoted to 
the courses by different colleges. There is some excuse for this 
variation due to differences in importance of some crops in different 
parts of the country, but even here there probably could be more 
uniformity. 

THE FIRST COLLEGE COURSE IN FIELD CROPS. 1 

William L. Slate. Jr. 2 

At the Chicago meeting of the Society last November, a step toward 
better instruction in agronomy was taken when place on the program 
was given to a discussion of teaching problems in crops and soils. 
The direct stimulus had its origin in the conference on instruction in 
grain grading, held in Chicago the previous September. The idea 
bore fruit in the conference on instruction in soils at the University 
of Kentucky last summer and again in the arrangement of our present 
program. 

The whole field of agriculture is relatively young and needs organ- 
ization. Every department is an experimental center in teaching as 
well as research. Many avenues are open for the interchange of 
ideas on investigational problems and are well used, but the teaching 
phase has received less attention, altho we all agree as to its im- 
portance. It would seem, therefore, that this society has a definite 
function to perform in bringing about an exchange of opinions and 
ideas and perhaps even in laying definite plans, thru committees, for 
the study of teaching problems. 

Last year the round table on " Teaching of Field Crops " brought 

1 Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 18, 1920. 

2 Agronomist, Connecticut Agricultural College, Storrs, Conn. 



6o 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



out very forcibly the fact that we are far from agreement in our basic 
points of view. For instance: 

1. Is there a science of field crops, or is it an application of botany, ento- 
mology and the like? 

2. If we recognize such a science, what is its relation to other subjects in the 
curriculum, particularly the pure sciences? 

3. What technical knowledge and skill should be included in courses in 
crops? 

These and many other questions were discussed without arriving at 
any definite conclusion or agreement. There is and always must be 
a variation in our teaching, based on region, college or university 
organization, and other local differences, but on the fundamentals 
there surely is some common ground. 

The first course in field crops has been chosen for this discussion 
for several reasons : 

1. The fundamental courses, required of underclassmen, should receive our 
very best efforts. On this I am sure we are all agreed. 

2. Every agricultural graduate, no matter what his major, should be able to 
think intelligently in field crops. Therefore we commonly find at least one 
course in crops required of all students. 

3. The more highly specialized courses will, in a way, take care of themselves 

To discuss the subject intelligently, it is necessary to assume a point 
of departure, which may be stated as follows : 

There is, in my opinion, a real science of field crops; in other 
words, a body of information that belongs to the subject. For the 
solution of many of the problems involved, or for the explanation of 
technic, other fields are drawn upon freely. This is common to all 
sciences. Chemistry calls upon physics and botany upon chemistry, 
but we do not consider botany as applied chemistry. In other words, 
field crops is not merely an application of the pure sciences. The 
problem i- crop production, and we draw on other fields when there 
is need. For instances, I do not concede such a subject as agricul- 
tural botany. Thai phase of botany is included in field crops and 
horticulture. But for real botany there is ail important place. 

To illustrate a farmer is producing tobacco. The control of 
Thelavia is a crops problem. Plant pathology has helped to solve it, 
e fanner need not be a specialist in that subject to handle the 
disease successfully. In a course in crops, therefore, the control or 
cc should be taught, with just enough plant pathology to give 

•' < rea OH lot the practice. This does not mean that a course in pure 
plan' patholotfs would not be very valuable to the student, but it 



SLATE : FIRST COURSE IN FIELD CROPS. 



6l 



should not be the so-called practical course. That phase should be 
covered in courses in crops and horticulture. With this viewpoint 
in mind a first course, called Field Crop Production, presents the 
following problems : 

I. Type of Course. On this point, there is a divergence of opinion 
and practice. I submit that every agricultural graduate should have 
a general knowledge of crop production. The chief function of 
undergraduate courses is not to train specialists, but to give the 
student the general information necessary for farming and a broad 
outlook on agricultural problems. With this in mind, the course 
should include all the important crops with stress laid on those most 
important in the region. 

II. Aims of the Course. The student should — 

1. Be able to recognize the important field crops, plant and seed, and some 

varieties of those important in the region. 

2. Know the simpler fundamental principles of plant growth. 

3. Know good seed and how to get it. 

4. Know cultural, practices for the important crops. Here would be included 

control of diseases and insects. 

5. Be able to lay out a cropping system for a given set of conditions. 

6. Know something of the sources of information. 

In fact, he should be able to think reasonably intelligently in field 
crops, to handle his crop successfully and know how and where to 
get help on special problems. 

III. Course Content and Method of Teaching. This would natu- 
rally vary with the region, the season given, and the amount of time 
assigned. We are using a general text, Professor Montgomery's. 
Since forage is vital in New England agriculture, we have stressed 
meadows and pastures, but the most important features are the 
problems and the relation of the laboratory work to these problems. 
As an example, each laboratory section makes a study of four 
pastures. With this as a basis, they are given a problem which 
involves not only the information gained in the pasture study, but 
data that must be sought in the text and other sources. 

Another feature we have found very useful is the " Term Prob- 
lem." Xear-by farms are chosen and for them cropping systems are 
planned. Many details are included, such as manure produced, seed 
used, machinery necessary, dates for various operations, disposal of 
crops, etc. This farm also serves as a basis for many minor prob- 
lems in connection with the various crops studied. 

IV. The Relation to the Sciences and other Courses. This phase 



62 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



has been touched upon, but it might be well to emphasize the point 
that there need be no conflict. As to overlapping, it should be borne 
in mind that very few of us absorb an idea at the first presentation 
and that every problem has several sides, all of which must be seen 
before a full understanding is reached. 

The friction arises when an instructor in crops spends a large 
amount of time teaching botany or plant physiology, thinking it neces- 
sary for a proper understanding of crop production, or when the 
course in botany dips into crop production as its chief source of 
subject matter. In neither case is this necessary. There is room 
for both. 

V. Relation to the Specialized Courses hi Crops. Here there 
should be no difficulty. If there is not enough material left after the 
first course is given, then we should give the one only. Since none 
of us would take this position, the general course should furnish the 
interest that will urge some students to pursue various phases further, 
but the attitude should not be one of proselyting. The value of the 
first course is lost when this is the aim. It should be kept in mind 
that we are training farmers first and specialists second and that the 
great majority of the student body will receive no further instruction 
in this subject. 

VI. Relation to Farm Experience and High School Agriculture. 
This raises a variety of problems. In the States where the great 
majority of freshmen come from farms, many contacts and experi- 
ences ran be omitted. The problem method can be even more 
emphasized, for the men have a farm background. Where high 
school agriculture is common it may be necessary to divide the class, 
or it is conceivable that students from certain high schools might be 
excused from this course. 

VII. Place in the Curriculum. In the Opinion of the writer, the 
coura under discussion may be required in the freshman year. An 
objection is immediately raised, that of the botany prerequisite. In 
answer, let u> suppose a group of farmers. Is it not possible to 

teach them tin- fundamentals of crop production without a previous 

Course in general botany? It takes better teaching, to be sure, but it 
i> being done. In the ease of the student, botany following or 
paralleling tln^ course serves as an elaborator. a clarificr. 

Bj making this a freshman Course, the student has his feet at 

once on solid ground. II* begins w ith the fundamentals of his pro- 

n In ci-cs where farm experience is a prerequisite to admis- 
sion or where practically all Students are farm bred, such a course 



STEVEXSOX AXD BROWN : TEACHING SOILS. 



63 



might well be postponed until the sophomore year. In that case the 
type of course would be modified somewhat. This does not assume, 
however, that when given in the freshman year the course must be of 
high school caliber. It can be made a " man's job " without recourse 
to the extremely technical. 

VIII. Amount of Credit Allowed. It is possible to teach the 
course in a single semester, by all means the fall in the north, allow- 
ing three hours' credit. Four or five credit hours would be much 
more satisfactory. 

THE TEACHING OF SOILS IN AGRICULTURAL COLLEGES. 1 

W. H. Stevenson and P. E. Brown. 2 

The conference of soils teachers held in Kentucky last June is 
ample proof that the men who are responsible for the soils courses in 
the agricultural colleges of this country are determined to improve 
the teaching of soils of collegiate grade. This is a wise and timely 
decision for many reasons. During the past twenty-five years little 
or no organized effort has been made by our agricultural college 
teachers to outline and develop courses in soils that are reasonably 
uniform, that cover the whole field in logical sequence, that command 
and hold the interest of students, and that act as a challenge to really 
competent men to specialize in soils and pursue graduate study along 
this line. Even a superficial study of the soils courses that are out- 
lined in many current college catalogs conclusively proves this 
statement. 

At least a few of O U 1 c t gricultural college faculties apparently fail 
to look upon instruction in soils as worthy of a place of real im- 
portance in the curriculum. This attitude is no doubt due in part to 
the fact that in some colleges the soils work has not been presented 
in a forceful manner by competent teachers. But is not the reai 
reason found in the fact that in many cases the instruction in soils 
does not measure up to the standard that it should have reached at 
this time, especially in the beginning or elementary courses? We 
may not agree on this point and it may not be important. However, 

1 Read by the senior author at the thirteenth annual meeting of the Ameri- 
can Society of Agronorrry, Springfield, Mass.. October 18. 1920. 

2 The senior author is vice-director of the Iowa Agricultural Experiment 
Station and professor of farm crops and soils and the junior author is chief 
in soil chemistry and bacteriology, Iowa State College, Ames, Iowa. 



64 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



we must agree that now is the time carefully to plan more satisfac- 
tory courses in soils for our agricultural colleges to the end that many 
well-founded criticisms of our present courses may be eliminated and 
soils work for students may be made more interesting and stimulating 
and truly helpful. 

The status of the teaching of soils in a large number of our agri- 
cultural colleges seems to warrant the conclusion that more satis- 
factory results may be secured by uniting all phases of soils instruc- 
tion in one organization or department. We do not believe that the 
student gets the best work in soils when the instruction in this subject 
is given by two or more collegiate departments. This arrangement 
almost invariably leads to overlapping in the courses and to a failure 
to obtain and hold the interest of the student. Experience teaches 
that only when all soils work for students is organized as a unit do 
we get the most satisfactory results in the outlining and development 
of courses and in creating an atmosphere that tends to make students 
become really enthusiastic about the study of soils. 

Failure to organize the work on this unit basis is due almost 
entirely to the attitude of teachers of pure science and of administra- 
tive officers. Teachers of science are tempted to teach soils because 
this applied science opens a most interesting field that is naturally 
popular with students. The result of this attitude on the part of 
science teachers often leads to placing some of the work in soils in 
the chemistry or geology or some other department of the institution 
and in this way it is broken up and much is lost from the standpoint 
of unity, atmosphere, and appeal to the student. 

Many administrative officers apparently do not fully grasp the idea 
that the science of soils is an applied science and is therefore a real 
unit. The science of soils is based on several pure sciences, chief 
an 01 g them being chemistry, physics, and bacteriology, but this is not 
a valid reason Eor considering soils a part of chemistry, a part of 
physics, a part of bacteriology, or a pari of any other pure science. 
On the Other hand it should be regarded as a definite applied science. 
En ipite Of this fact •mnc college officials persist in the belief that 
Certain phases of soils instruction should be given by one or more of 
the science departments, in most cases chemistry, and have not seen 
the necessity of uniting all phases of it in one organization. This has 
proved to be a real handicap in teaching soils in a satisfactory way 
and in not a few cases it has interfered to some extent with the 
development of experiment station work in soils. 

Another factor that sometimes interferes with the normal develop- 



STEVENSON AND BROWN : TEACHING SOILS. 



°5 



ment of the soils courses in an institution is the fact that the teach- 
ing of soils is based too largely upon the local experiments. It is 
certainly true that the experimental data of any station should be 
of great value in connection with the instruction in that institution 
and should be utilized. In some cases, however, the courses in soils 
have been based so largely on the work of the local station and the 
problems of the State that time and opportunity have not been avail- 
able for a consideration of some exceedingly important phases of the 
general subject of soils. For instance, so much time may be devoted 
to a classroom and laboratory study of the field experiments of a 
given station that the classes are cut off from a study of certain 
fundamental principles of fertility that are vastly more worth while. 

Soils teachers must meet still other difficulties and problems. A 
list of four important problems includes the following: 

1. The number and sequence of courses and the amount of work in 

each. 

2. The subject matter presented in each course. 

3. The character and amount of laboratory work. 

4. The general method of presenting soils instruction to students. 

A brief consideration of these problems shows, in the first place, 
that no college can teach the subject of soils properly in two or even 
three quarter or semester courses and yet some institutions offer 
little or no soils work beyond this limit. The results in these cases 
of course are wholly unsatisfactory from the standpoint of the stu- 
dent and the instructor. The student gets instruction in a very 
limited part of the subject of soils or he is confused and misled by a 
veritable jumble of facts and data concerning physics, fertility, 
manures, bacteriology, and possibly surveying and other subjects. 
The majority of our colleges, however, have made commendable 
progress in recent years in regard to the number of courses in soils 
that are offered. 

We are of the opinion that not less than four or five courses, each 
running thru one quarter or term, should be required in a 4-year 
agricultural course in the case of students majoring in farm crops, 
soils, animal husbandry, farm management, or horticulture. These 
courses should include an introductory course dealing with soils in 
general and courses in fertility, manures and fertilizers, bacteriology, 
and management, ottered in the order named. The work in soils 
for other students should be adapted as far as possible to meet their 
special needs ; this applies to students in agricultural engineering, 



65 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



dairying, forestry, agricultural economics, agricultural journalism, 
agricultural education, and in special lines such as combined courses 
in home economics and agriculture. Furthermore, it is not necessary 
nor desirable that the general agricultural student be required to take 
highly specialized and more or less technical courses in soils. Such 
courses should be offered as advanced electives which may be taken 
by those students who are preparing for positions that demand 
special soil training. 

The nature of the subject matter in the general or required courses 
may be determined very satisfactorily by keeping in mind the fact 
that the general agricultural student should study those fundamental 
principles of soil science which will train him for any agricultural 
work and which will fit him to farm successfully. This means that 
the basic soil courses will deal not only with science as related to 
soils and the fundamental principles involved, but will also emphasize 
farm operations and farm practice. An extended experience has 
proved that the majority of students in our agricultural colleges are 
willing to dig for principles with great earnestness and enthusiasm 
when they know that these principles will be used in due time in the 
classroom or laboratory in working out practical, every-day problems 
of the farm. Certainly no teacher of soils in this day should hesitate 
to use practical illustrations and point out the application of prin- 
ciples to soil management problems. Failure to do this is not neces- 
sarily an earmark of superior scientific attainments and it may raise 
the question with some students as to whether or not the instructor 
is really competent to tie up the principles of soil science with prac- 
tice. In this connection we would suggest that one of the real needs 
ol - ila teachers at tin's time is for text books for beginning students 
that do not attempt to cover the whole subject, but that deal fully 
and in a not too technical manner with one phase of the work. In 
book is offered thai includes work in physics, fertility, manures 
and fertilizers, bacteriology! and management, or two or more of 
these Subjects, it is desirable that each of these lines be treated as a 
Unit. This arrangement will prevent confusion on the part of the 
student and w ill enable the teacher to present his work in the proper 
sequence. 

\\ <■ realize that the foregoing statements regarding the most satis- 
factory innnbci of oils courses and the subject matter in each are 
tOO general t" b€ of the greatest value. For tliis reason we present 
Ome faCtfl about the soils work at the Iowa State College, with the 
hope that tin y m;i\ he of some value to soils teachers elsewhere and 



STEVENSON AND BROWN : TEACHING SOILS. 



67 



may help to illustrate the points that we are endeavoring to emphasize. 

It is worthy of note that the soils courses in Iowa have been de- 
veloped gradually thru a period of eighteen years. They represent 
the efforts of a relatively large number of soils teachers who have 
endeavored earnestly to build up a group of courses that meet the 
requirements of about one thousand agricultural students, who hold 
widely different views regarding the amount and character of the 
soils work that should be included in their individual courses of study. 
On account of this attitude on the part of our students it is necessary 
in Iowa to offer courses in general soils, fertility, physics, manures 
and fertilizers, bacteriology 7 , management, and surveying, including 
instruction that is quite elementary and also that which leads to the 
degrees of Master of Science and Doctor of Philosophy. The total 
annual student enrollment in these courses for the last eight or ten 
years, with the exception of the war period, has averaged approxi- 
mately seven or eight hundred. 

The introductory course at Iowa is called " Soils." Until two or 
three years ago this course was called Soil Physics and included 
rather general work along physics lines. The second course is known 
as " Soil Fertility " and not " Soil Chemistry." In our judgment the 
former name is much superior to the latter. The work in fertility 
may include a consideration of manures and fertilizers but here these 
subjects are taught in a third course called " Manures and Fertilizers." 
" Soil Management " is a final course for the general student. A 
brief course in " Soil Bacteriology " is offered as an elective preced- 
ing the work in " Soil Management." This is required for farm 
crops and soils students. In our judgment the first four courses 
represent the minimum amount of soils study that should be required 
of general agricultural students and we would make " Soil Bacter- 
iology " an additional required course for farm crops and soils 
students. 

Our first course, " Soils," includes a study of the origin, forma- 
tion, and classification of soils. The soil provinces, regions, series, and 
types in the United States are considered and the purposes, methods 
involved, and value of a soil survey are taken up. This is followed 
by a more or less complete study of the soil areas, groups, and types 
in the State, utilizing our soil surveys as a basis. Special emphasis 
is placed on a study of the so-called abnormal soils of the State, such 
as the peat, alkali, gumbo, hardpan, and push soils. Soil erosion and 
its control, dry farming, and alkali soils are some of the special sub- 
jects which are touched upon briefly in this course. 



68 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The course in " Soil Fertility " begins with a study of the com- 
position of soils in general, including a consideration of all plant-food 
constituents and compounds, available and unavailable plant food, 
the constituents necessary for plant growth, the chemical analysis 
of soils, its purpose and value, the elements likely to be lacking in 
soils, and the average content of agricultural soils in these constitu- 
ents. This is followed by as complete a study as possible of the 
composition of the soils of the State. The principles of soil fertility 
are then presented broadly, special attention being devoted to the 
removal and return of plant food, the theories of a permanent agri- 
culture, and the factors which are the basis of rational systems of soil 
management. Each of these factors is then studied in detail, with 
special emphasis on soil acidity and liming, phosphate fertilizers, or- 
ganic matter, and nitrogen. 

The course in " Manures and Fertilizers " includes a study of 
commercial nitrogen, commercial potassium, indirect fertilizers, and 
crop stimulants in relation to up-to-date systems of soil management. 
An extended study is made of complete commercial fertilizers, with 
special emphasis upon their place in the agriculture of the State. 
Farm manures and green manures are also studied and the course 
is concluded with a review of the principles that underlie field experi- 
mentation and a study of the data from the Iowa soil experiment 
fields. 

The " Soil Management " course is naturally the culmination of the 
general soils work and is outlined so as to fix in the mind of the 
student the facts presented in the preceding courses. Approximately 
twenty-five actual farm problems are presented by the instructor, the 
Student being required to hand in a written statement explaining in 
detail just how he would proceed to work out the problem under 
deration on his own farm. These statements are then discussed, 
u far aa time permits, in the class, for the purpose of pointing out 
and explaining practical methods of dealing with the problems 
on the farm. This COUfge is one of the most popular in the institu- 
tion and many students have said that it gives them just the type of 
information and training that they need along soils lines to prepare 
them for fanning, teaching, county agent work, and similar activities. 

The course in "Soil Bacteriology " includes a study of the num- 
bers and kinds of bacteria in soils and their various activities, special 
emphasis bring placed upon the relation of these organisms to the 
production of available plant food, the fixation of nitrogen, and their 
general relation to soil fertility and permanent agriculture. 



STEVENSON AND BROWN : TEACHING SOILS. 



6 9 



Let us now consider briefly the laboratory work that is offered in 
connection with these courses. The laboratory method of instruc- 
tion that has been followed quite generally in many institutions in 
recent years is undoubtedly open to severe criticism. Xo doubt it is 
time to revise much of the laboratory work in soils in order to make 
it fit in with the lectures and give the student a new body of facts, a 
new viewpoint, and provide him with useful information. Our 
experience proves that it is possible to give laboratory work in con- 
nection with the general soils courses that does not demand of the 
student an immense amount of uninteresting routine of more than 
doubtful value, such as is often carried on in connection with soil 
physics and soil fertility courses. 

The laboratory work of our introductory course is based upon a 
study of the soils of the State as taken up in the soil survey reports. 
This is followed by field studies involving the actual preparation of a 
soil map of an assigned area and a study of the characters of soils in 
the field. Soil survey reports then serve as the basis for a specialized 
study of the soils of individual counties which are chosen to represent 
the large soil areas of the State. Discussions, quizzes, and the writ- 
ing of reports make up this work. The field studies are carried out 
under the guidance of the instructor but the student is required to 
prepare his own map, describe all the soil types found, and prepare 
his report. The work as a whole is so arranged and handled that it 
is both interesting and instructive to the student. He acquires first- 
hand knowledge of soils and a broad viewpoint of the whole subject, 
besides gaining information which will be of great value to him when 
he returns to manage his home farm or when in some other capacity 
he is called upon to solve soil problems. 

The laboratory work in soil fertility as offered in many institutions 
has been criticized, and when, as is true in many cases, it involves 
merely an analysis of fertilizers and soils, such criticism is warranted. 
In our institution the student's home farm forms a basis of the 
laboratory work in soil fertility. The purpose is to have each student 
plan a system of permanent fertility for his own soils. To do this 
he must know how much plant food the crops remove and what 
amounts are present in manures, fertilizers, and crop residues. To 
get this information he must make some analyses but the emphasis 
is of course placed upon the soil analyses. It is believed, however, 
that a few typical materials should be analyzed. These analyses are 
clearly understood to be secondary to the main part of the work, 
which is the planning of a system of soil management for the farm. 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Reports are required to be complete and recommendations accurate 
and the laboratory periods prove very profitable to the student. 

The laboratory work in manures and fertilizers is essentially the 
same as that in soil fertility. However, there is this difference. The 
former deals with soil management problems from the standpoint of 
a grain farm, the latter from the standpoint of a livestock farm. 

The course in " Soil Management " does not include laboratory 
work. In soil bacteriology, laboratory work may or may not be 
included. The laboratory course as given in Iowa includes a count- 
ing of numbers of bacteria and a measurement of the ammonifying, 
nitrifying, deodifying, and azofying power of soils. Soil from the 
student's home farm is secured when possible and the work is then 
much more satisfactory. As in other courses, the emphasis is placed 
upon the interpretation of the results and not upon the mere securing 
of them, for the real value undoubtedly lies in such interpretation. 

The advanced courses in soils may be variously outlined and may 
be arranged to fit local or curriculum conditions. Opportunity should 
undoubtedly be offered, however, for electives in soil physics, soil 
fertility, soil bacteriology, and soil surveying. There should also be 
seminars and courses dealing with special problems. In Iowa courses 
are offered under the following names : Soil Physics ; Advanced Soil 
Physics; Advanced Soil Fertility; Advanced Soil Bacteriology; Dry- 
Farming Soils ; Soil Mycology and Protozoology ; Soil Surveying ; 
Advanced Soil Surveying; Special Problems in Soil Physics, Fertility, 
Bacteriology, or Surveying; Advanced Special Problems in each of 
these lines; Junior and Senior Seminars; and Theses. Graduate 
courses leading to the degrees of Master of Science and Doctor of 
Philosophy are also offered in Soil Physics, Soil Fertility, Soil Bac- 
teriology, Soil Humus, and Soil Management. All these courses 
excepl those especially designed for graduate students are carefully 
and definitely outlined for class use and so arranged as to give the 
student excellent training in the particular subjects that he may 
pursue. The graduate work of course is outlined for each indi- 
vidual student and is highly specialized. 

The teaching of soils to undergraduate students may certainly be 
made interesting :i]u \ highly effective if it is properly organized, if 
courses arc offered that are wisely outlined, if laboratory work is 
given that deaU primarily with problems of scientific and practical 
interest, and if competent instructors are secured who never lose sight 
of the fact that soil science If a practical, applied science which must 
be presented to the student in a way that will enable him to secure 
a definite understanding of soil principles as applied to farm problems. 



miller: the teaching of soils. 



71 



THE TEACHING OF SOILS. 1 

M. F. Miller. 2 

Three papers have appeared recently in the Journal of this So- 
ciety having to do with the teaching of soils. The tone of these 
papers indicates a general feeling that improvement in methods of 
teaching have not kept pace with the advancement in soil science. It 
seems that we have reached a point where very definite steps should 
be taken to put the subject upon a more satisfactory teaching basis, 
and to consider the needs of students as well as the relation of the 
subject matter to that of other agricultural courses. 

You are doubtless aware that as a result of the publication of the 
above mentioned papers a few of the interested men took the initia- 
tive in calling a conference of soils instructors for the purpose of 
comparing ideas and arriving at some fundamental principles which 
might be rather generally applicable. A brief report of the findings 
of this conference was published by the secretary in the last issue of 
the Journal 3 of this Society, and some brief notes regarding it 
appeared in the last issue of Soil Science. 4 I wish therefore to con- 
sider some of the findings and conclusions of this group of men repre- 
senting unofficially, yet rather directly, the membership of this 
Society. 5 

It might be said w r ith reference to the nature of this conference 
that it was very informal. No papers were presented, altho an out- 
line to guide discussion had been prepared. The conference con- 
tinued thru two days, thus giving ample time for full and careful 
discussion of the various questions involved. In was considered best 
to confine the discussions at this first conference largely to the intro- 
ductory soils course, its prerequisites, its place in the curriculum, its 
content, and its arrangement. The conclusions, therefore, have to do 

1 Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 18, 1920. 

2 Professor of Soils, University of Missouri, Columbia, Mo. 

8 Conference on elementary soils teaching. In Jour. Amer. Soc. Agron., 
12:211-214. 1920. 

4 Notes on the confeience on elementary soil teaching, held at Lexington, 
Kentucky, June, 1920, by P. E. Karraker, secretary. In Soil Science, 10:247. 
1920. 

5 Professor Miller was chairman of this conference. — Ed. 



72 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



with this course alone. I shall attempt to give the viewpoint of the 
majority of the men present upon the most important of these con- 
siderations, which are as follows. 

1. The introductory college course in soils should be a uniform 
course to be required of all agricultural students, and it should carry 
approximately five semester-hours credit or the equivalent. 

The desirability of an introductory course of a general nature 
seemed to meet with almost universal approval. At present there is a 
wide variation in the character of the introductory soils courses. 
Some deal largely with soil physics, some with soil chemistry, while 
still others cover a rather broad field in a somewhat superficial 
manner. Such a difference in character is due partly to different 
local conditions, partly to prevailing interests of the instructors, and 
partly to the comparatively recent development of soil science. It 
would seem, however, that the science has now reached a condition 
in which the giving of such a general course is feasible, and that the 
character of this course should be similar to those introductory courses 
offered in the pure sciences. 

It is believed further that soils is one of the fundamental subjects, 
regarding which all students should have a general knowledge re- 
gardless of the lines in which their specialization may fall. If this 
is the case it should be required of all students. While the length of 
such a course would necessarily vary somewhat in different institu- 
tions, it seems probable that a five semester-hour course, or its equiva- 
lent, would be sufficient to cover the field. 

2. This course should deal largely with the scientific principles 
underlying successful soil management in general, with such prac- 
tical applications as local conditions demand. The name of the 
course, where a descriptive name is required, should be "The Prin- 
ciple-, of Soil Management." 

It is realized that exact standardization of such an introductory 
COtirse is impossible, yel the subject matter should be as uniform as 
the conditions in the various institutions will allow. It should deal 
with principles, yet it should include such applications as will illus- 
i points under consideration and give the student a knowledge of 
how these principles are related to practice. Local conditions will 

determine the amount of such practical applications which should be 

included. ( kit fault of many beginning courses has been that they 
have been arranged With the idea that the student will take further 
work in the subject. I 'nder such ;i plan the general body of stu- 
dents, most of whom take little or no advanced work in that subject, 



miller: the teaching of soils. 



73 



has been given too little attention. Certainly an introductory course 
in soils designed for training agricultural students, particularly 
where such a course is prescribed, should give the student a general 
knowledge of the field. Such a plan seems not only good pedagogy 
but good departmental ethics. 

With such a fundamental general course there is little danger of 
degeneration into an indefinite discussion of prevailing methods of 
practice. In dealing with fundamental principles the course may be 
maintained of high collegiate grade^ comparable to the introductory 
courses in pure science, yet containing such applications to practice 
as will be of value to the student who goes into practical fields. How- 
ever, the character of the material presented should not be such as 
to emphasize solely the economic importance of soil management. 
While this is the thing which is commonly uppermost in the minds 
of farm-reared students, the teacher should at times get above purely 
economic considerations and emphasize the importance of soil knowl- 
edge to civilization as well as point out the broad relations of the 
subject to general science. 

3. The subject matter of the course should be presented by well 
correlated recitation, lecture, and laboratory work. 

I think we will all agree that in most instances the subject matter 
given in technical agricultural courses lacks somewhat in definiteness 
and in pedagogic arrangement. As a general rule agricultural in- 
structors are not well trained in pedagogy, and under the rapid de- 
velopment of soil science many instructors lack proper technical prep- 
aration. Nevertheless much improvement has been made in recent 
years. The introduction of standard texts has been very helpful. 
With a greater differentiation of work in agricultural colleges it has 
been possible for men to narrow their fields of endeavor and increase 
their efficiency. It seems therefore that the time is ripe for a thoro- 
going revision of the subject matter in such courses as the one under 
discussion. 

As a basis for discussion the five semester-hour course was taken as 
probably the most common, and an effort was made to reach an 
agreement regarding the division of time between lecture, laboratory, 
and quiz periods. Naturally, considerable differences of opinion 
developed with reference to this matter. There were two suggested 
plans. First, the plan of three recitation periods and two laboratory 
periods per week ; second, the plan of three lecture periods, one quiz 
or recitation period, and one laboratory period. The first plan is 
probably the most common in those institutions now giving a general 



74 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



introductory course. It was the opinion of the conference, however, 
that this is not the best arrangement. There is the danger that when 
as much as two laboratory periods per week are included this time 
will be taken up very largely either with physical experiments of 
doubtful value or with chemical work in which the students are more 
impressed with the technic of the operation than with the funda- 
mental facts which these chemical manipulations are designed to 
establish. It is believed that the average student would secure much 
more value from the course if the laboratory exercises were designed 
to give definite information. A general course in soils should teach 
soils and not chemistry or laboratory technic. There are of course 
institutions where the soils work is organized with that of agricul- 
tural chemistry in which the laboratory instruction might best con- 
sist largely of quantitative chemical determinations, but is seems 
doubtful if such an amount of chemical work is fair to the general 
student. Such work had best follow in elective courses. 

The plan of three lectures, one quiz, and one laboratory period 
per week met with the more general approval. The introduction of 
the quiz period is in line with plans of teaching introductory courses 
in the pure sciences. The purpose of this quiz is to clear up doubt- 
ful points in the minds of students, and to emphasize important 
phases of the subject, as well as to determine the accuracy of the 
students' knowledge. The subject of soils, when properly taught, is 
complex and difficult. Quizzes of such a nature that the student is 
caused to think and to arrange the facts he has gathered would seem 
to he ] .roper pedagogy. This is particularly true of a general course 
of this character offered early in the curriculum. 

The lecture method supported by a standard text is much pre- 
- i «1 to the u^e of a text alone or lectures alone. The text adds 
to the material given in the lectures and students should be held 
accountable for the subject matter in each. 

The laborator) or practicum work for a single period per week 
needs Special consideration. In the first place no work should be 
"■ red in the laborator} or practicum, the principles of which have 
• ol already been covered in the class room. Secondly, as has been 
■ ted, the material presented in the laboratory should be such as 

to imparl helpful information directly, rather than indirectly thru 

Complicated laboratory exercises which are of value mainly to the 
soils Specialist. It is doubtless on this part of the content of the 
eourse that there will he the greatest difference of opinion. hi 
order to provide a workable scheme of rather general application the 



miller: the teaching of soils. 



75 



conference spent a considerable period in preparing such an outline. 
This outline includes such subjects as the following: 

a. Study of minerals and rocks, and methods of weathering. 

b. Study of soil particles and soil classes. 

c. Determination of certain physical properties of soils, such as volume weight, 

porosity, etc. 

d. Study of soil organic matter. 

c. Determination of field moisture. 
/. Study of soil reaction. 

g. Study of fertilizer materials and lime. 

h. Certain field trips for studying soil formation, soil classes and types, and 

the use of fertilizer and lime. 

It is realized that such an outline is merely suggestive and time only 
will determine its value. Doubtless experience will suggest many 
changes. It does, however, give a working plan for trial and includes 
exercises which, where properly handled, will give the student in- 
formation of value. 

4. The minimum prerequisites of this course should be one year 
of general inorganic chemistry, one term of general geology, and 
either high school or college physics. Wherever practicable the work 
should be ottered in the sophomore year. 

It is desirable that some information on soils be available to stu- 
dents early in the course as a foundation for such subjects as field 
crops and horticulture. If the list of prerequisites be extended much 
beyond those mentioned, the work could not be offered before the 
junior year. Furthermore, for such a course as outlined these pre- 
requisites are all that are absolutely necessary, altho it is realized 
that more are desirable. The importance of placing the course as 
early as the sophomore year seems to outweigh that of fuller funda- 
mental training. 

The advantages of such a general introductory course as outlined 
are obvious. It would enable the general student to obtain in a single 
course a survey of the entire field. It would make possible a better 
standardization of subject matter, of texts, and of laboratory ma- 
terial. It would allow a fuller application of the principles of peda- 
gogy and would facilitate the transfer of credits from one institution 
to another. It is of course realized that the universal adoption of 
such a course is impracticable, but there seems little reason why it 
should not come into rather general use. Certainly the trend seems 
to be in this direction in the larger institutions. The conference 
agreed that the plan suggested should be given trial in as many 
institutions as could make the proper arrangements and that another 
meeting should be held a year or two hence to discuss developments. 



~6 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



I think I agree in general with the various recommendations of 
this conference. They certainly look toward improvement. There 
are. however, certain matters which the conference did not consider 
but which seem important. 

I am of the opinion that much of the loose teaching which has 
been done in agricultural colleges, not only in soils but in other lines 
of agricultural instruction, has been due to the scheduling of too 
many courses. There is naturally a desire on the part of every de- 
partment head to popularize his work and appeal to students. Often 
this results in multiplying courses. In the more wealthy institutions, 
well supplied with instructors, this may be justified, but where the in- 
structor's time must be extended over a number of courses, efficiency 
in teaching is certainly lessened. I am convinced that a few courses 
in which the subject matter is well worked out and pedagogically 
arranged will give best results. Where certain specialized courses 
are really needed, these usually can be offered in alternate years 
rather than every year. Such a plan saves the instructor's time and 
increases efficiency. 

There is another obstacle to thoroly successful teaching which 
seems to me is common in many institutions and that is the interfer- 
ence of experiment station work and the general routine of office 
work with which many instructors are charged. My experience has 
been that teaching is the project most likely to be slighted. Men 
go before a class with little preparation. Some institutions have met 
this difficulty by forming separate station staffs, altho in the weaker 
institutions such a plan is rarely possible and there is some doubt in 
my mind as to its wisdom. With the increasing numbers of students, 
however, I take it that such a division of work will become more 
common. Bui for those men who must work under a dual or triple 
responsibility much care and labor is necessary that the subject 
matter of their courses be properly arranged and presented. 

It has always seemed to me that the average agricultural college 
instructor takes particular satisfaction in minimizing the value of 
pedagogy in teaching, or at least he is very sceptical of its value. 
I >' ml »t some of this has resulted from the intricate systems of 
;ogy taught in many de partments of education and in teachers' 
■ '< . Imi: much of it is due to a lack of any knowledge of peda- 
gogy on the part of the instructors themselves. There are, of course, 
exceptionally effective teachers who know little pedagogy and doubt- 
less in some lines (rarely in agriculture) there are those who give 
•"<> much attention to methods and too little to the preparation of 



miller: the teaching of soils. 



77 



good subject matter, but certainly the teaching of soils in our colleges 
of agriculture would profit greatly by the application of the more 
important principles of psychology and pedagogy. In the University 
of Missouri the Dean of Agriculture has insisted that young instruc- 
tors take one or more courses in the School of Education. Possibly 
this same plan is being followed in some other institutions. In my 
judgment, satisfactory soils teaching from this time forward will be 
based, not only upon a thoro training in soil science, but on such a 
knowledge of pedagogy as will enable the instructor to present the 
material to the best advantage. I believe the time is ripe for placing 
the teaching of soils, particularly the introductory courses, on a sound 
pedagogic basis. 

Finally, it seems to me that the relation of soils courses to others 
in the curriculum should be given more consideration. Every one 
who has had experience in arranging curricula realizes that there are 
many diverse interests and almost every curriculum is a compromise. 
Nevertheless there are certain principles which it would seem might 
meet with more or less general approval. Mention has already been 
made of the fact that some knowledge of soils is desirable in the 
teaching of field crops and horticulture. To these might be added 
farm management, agricultural engineering, and even certain courses 
along animal lines. It would certainly seem unwise, therefore, to 
postpone the first soils course until the junior year. It is of course 
possible to give elementary instruction in this subject in the freshman 
year, and I think some institutions have provided for this in order to 
pave the way for other courses. Such a plan does not seem advisable, 
however, since with so little fundamental training on the part of the 
students the work would be largely of secondary school character. 
The compromise of a sophomore course, as suggested by the confer- 
ence, seems best. 

Where institutions offer a general introductory course in field 
crops there seems to be no plan of universal adaptation which will 
allow soils work to precede it. Some colleges are offering this 
course in the freshman year, others in the sophomore year. In the 
latter case the soils work may precede, or run parallel with it, accord- 
ing to the methods of scheduling and sectionizing the classes, but it 
seems clear that in many cases the introductory course in field crops 
must be given without a knowledge of soils on the part of the 
students. Where such a course consists partly of the principles of 
crop production it seems almost imperative that the work include 
something regarding soil tillage and seed-bed preparation of import- 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



ance in the production of each crop. For the farm-reared student 
who is familiar with the practical handling of soils such soil prin- 
ciples will be quite readily grasped without a previous course in 
soils, but the city-reared student is at a decided disadvantage. It 
would seem the part of wisdom for the instructors in soils and field 
crops to cooperate closely in the work of handling both these intro- 
ductory courses. While the crops instructor may be compelled to use 
considerable soils material, the soils instructor must to a certain ex- 
tent draw on crops subject matter as well. 

There are other courses commonly offered in soils and crops in 
which an overlapping of subject matter is necessary. In fact, these 
two lines are so closely allied that entire separation, with the excep- 
tion of a few specialized courses, is impossible. In courses dealing 
with production the two subjects must merge. Such courses are 
commonly listed under such titles as soil management, field crop man- 
agement, and crop rotation. Certainly in all such courses the subject 
matter of soils and crops must be to a considerable extent combined. 
Unless the instructors cooperate closely and arrange the subject 
matter of the courses carefully, repetition is unavoidable. Worse 
than this, conflict in statement of fact or contradictory recommenda- 
tions are almost certain to be made. This is one of the inevitable 
results of extended specialization and it should be corrected. In 
general our courses have profited greatly by restricting the field of 
the instructor and it is the duty of department heads to avoid in so 
far as possible the difficulties which arise. It is only thru such watch- 
fulness on the part of these men and thru close cooperation on the 
part of instructors that the greatest efficiency of instruction may be 
attained. 



BEAUMONT: INTRODUCTORY SOILS COURSE. 



79 



THE INTRODUCTORY COURSE IN SOILS. 1 

A. B. Beaumont. 2 

The content of the laboratory work usually forming a part of the 
introductory course in soils as given in our agricultural colleges has 
quite appropriately been questioned. Incidentally the content of the 
entire course and methods of presentation have come in for discus- 
sion, but the nature of the laboratory work seems to be the bone of 
contention. 

From the papers 3 presented in the Journal of the Society, there 
appear to be at least two schools of thought on the subject ; first, those 
who would limit the laboratory work to operations which the student 
will be using, or at least w T hich will be of direct value, in post- 
graduation activites, and second, those who would have the laboratory 
work include, in addition to the utilitarian exercises, those which may 
enlarge the student's vision and stimulate his interest. These remarks 
apply to the so-called average 4-year student who has only an average 
interest in soils and not to one who is specializing in the subject. 

An analysis of the possible values of the laboratory study of soils 
indicates at least six possibilities. They are : 

1. To acquaint the student with materials. 

2. To teach soil science. 

3. To teach principles involved in soil investigations and in soil management. 

4. To ascertain definite information concerning specific soils. 
5 Formal discipline. 

6. To arouse and stimulate interest in soil science. 

The first group of possibilities resides first in those exercises in 
which one studies materials such as soil classes and fertilizing ma- 
terials with the obvious aim of becoming familiar with them and, 

1- Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 18, 1920. 

2 Professor of Soils, Department of Agronomy, Massachusetts Agricultural 
College, Amherst, Mass. 

3 Karraker, P. E., What is the value of the usual laboratory work given 
in general soils courses? In Jour. Amer. Soc. Agrox., 11:253-256. 1919. 

Buckman, H. O., The teaching of elementary soils. In Jour. Amer. Soc. 
Agrox., 12: 55-57. 1920. 

Smith, R. S., Introductory courses in soils. In Jour. Amer. Soc. Agron., 
12: 58-60. 1920. 



80 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



second, in exercises in which the avowed aim is something else, but in 
which the unavoidable handling of materials forces familiarity. 

Among the latter may be mentioned the study of specific, gravity 
and hygroscopic moisture. This group also merges into the second, 
in which the principal aim is the study of soil science. In this second 
group we have such exercises as the study of mineral constituents, 
soil separates, the colloidal state, hygroscopic moisture, etc. 

The study of principles of soil investigations and soil management 
includes exercises in mechanical analysis and estimation of organic 
matter and lime requirement. The importance of these exercises lies 
not in the accuracy of manipulation or fineness of detail, but in the 
clear demonstration of the principles involved. It seems that some 
teachers have missed or lost sight of this important point. It is quite 
possible for a student to become bewildered by details and thus miss 
the fundamental principles involved or, figuratively speaking, he is 
unable to see the woods because of the trees. 

The ascertaining of definite information concerning specific soils, 
especially those brought from home by the student, certainly lends 
interest to the student's work. However, beyond narrow limits it is 
a questionable procedure pedagogically and, from the standpoint of 
direct use of student's results in 90 percent of the cases, it is worth- 
less. Bear in mind that we are speaking of the introductory course 
in soils. 

For formal mental discipline it seems that some of the more diffi- 
cult laboratory exercises with soils would serve as well as any labora- 
tory work. But the formal discipline theory of education as usually 
ascribed to John Locke has fallen into disrepute from which probably 
it will not be resurrected. 

From the standpoint of arousing and stimulating interest in soil 
science a great many laboratory exercises may be justified that could 
not he approved from the standpoint of the student's post-gradua- 
tion activities. This is indeed worth while because it is from this 
class of undergraduates thai most of the future agronomists will be 
recruited. Who can forecast the ultimate results from the stimula- 
tion of a Student's interest in soil science by a properly conducted 
exercise on the colloidal condition of soils or absorption of plant 
food by soils? 

A COUrse in K>ils thai limit- BUbjed matter to that which the stu- 
dent apparently will use in post graduation activities is short-sighted 
and nonprogrc ive. Sncli is the character of the education of primi- 
tive peoples. The history of education 4 shows that progress really 
I 1'. \ Sfiwlriit's History of Kriiiral ion, p. 12. Macmillan, [916. 



BEAUMONT : INTRODUCTORY SOILS COURSE. 



81 



began with the education of the individual beyond his immediate 
personal needs. Thus the Athenians are cited as a notable example 
among the first peoples to make their education progressive. 

Our graduates, even those who are to deal with practical applica- 
tions only, must have information beyond what is needed for every- 
day activities if they are to be able to grow and to measure up to 
opportunities. They must have vision as well as a reserve of in- 
formation. ' After graduation they should not be forced to work up 
to their capacity at all times. There should be for them an academic 
margin of safety. This is especially necessary for those who may 
engage in teaching or research. 

Recently we heard a leading agronomist, a director of one of our 
leading experiment stations, say to a group of county agents and 
extension workers who were thirsting after the science of soils and 
crops, that it is well for one to have a few hypotheses and theories ; 
even heresies, tucked back in his head, for one never knows when 
they may be convenient in helping explain things otherwise inex- 
plicable. 

In connection with the strictly laboratory course above discussed 
there should be well correlated field work consisting of observations 
and problems in soil management. Such field work will tend to 
show the student the practical application of his studies, arouse his 
interest, introduce problems, and give him practice in applying his 
knowledge. 

Of course, many will admit the value to be derived from most of 
the exercises usually presented. The point of disagreement is in 
regard to the proper balance. The recommendations of the recent 
conference of soil teachers is a step in the right direction. 

It appears that laboratory demonstrations by the instructor should 
be given more importance than they have been. By the use of 
demonstrations many of the more difficult exercises can be given in 
a shorter time and at less expense without impairing their pedagogical 
value, and thereby save time for field work and problems in soil 
management. . 

The above remarks apply to courses for 4-year college students. 
For our 2-year and other short course students the same general 
principles apply with modifications. In general the exercises in 
which the student is getting practice for post-graduation activities 
should be magnified at the expense of the others. There should be 
more field work and more problems in soil management. 



82 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



THE MICHIGAN PLAN FOR DISTRIBUTING IMPROVED CROP 

VARIETIES. 1 

J. F. Cox. 2 

Widespread interest is at present being manifested in organized 
movements to obtain the extensive distribution of dependable seed 
of high yielding crop varieties. Crop improvement associations, ex- 
periment associations, and corn growers' associations have been or- 
ganized in many States for this purpose. With the formation of the 
International Crop Improvement Association marked impetus has 
been given to this work. 

Within a short time there should develop a more or less stand- 
ardized method of State organization for the purpose of distributing 
improved varieties, as a result of the interchange of ideas among 
representatives of States engaged in this work. 

Recent progress along the lines of testing, developing, increasing, 
certifying, and distributing seed of improved varieties in Michigan 
may therefore be of some interest to agronomists in States where 
such work is contemplated or under process of development. 

Several important changes in the plan of obtaining rapid distribu- 
tion of dependable varieties have been made during the past year and 
have greatly increased the effectiveness of this work in Michigan. 
The initial distribution of varieties to members of the Michigan Crop 
Improvement Association is no longer made in small lots of from sev- 
eral pound- to a bushel, but means have been provided for the grow- 
ing of large increase fields on the Experiment Station Farm which 
will make possible the distribution of substantial quantities of seed at 
co^t to members of the association. 

The Held inspection system has been placed on a definite basis 
thru the action of the directors of the Crop Improvement Asso- 
ciation in fixing the responsibility for the direction of this work with 

the Farm Crops Department of the Michigan Agricultural College, 
tlx- co-t being borne by the association. 

Seed certification and guarantee is made by the Certification Com- 
mittee of the Crop [mprovcmcnl Association, based on recommenda- 

1 fontrihution from the M i< ln^aii Agricultural College, East Lansing, Mich. 
]<<<<\\r,\ for puhlication I )<-cctnher iX, 1020. 
- I'rofr- or of Farm Crop Michigan Agricultural College. 



COX : THE MICHIGAN PLAN. 



83 



tions made by field inspectors. In addition to the field inspection a 
careful analysis and germination test is made of thrashed samples of 
seed. 

Perhaps the most important step in the development of the machin- 
ery of distributing improved crops was brought about in Michigan 
thru the establishment of the Farm Bureau Seed Department on 
April 1, 1920, with J. W. Nicolson, former secretary of the Michigan 
Crop Improvement Association, as manager. 

The sale of seed produced and certified by the Crop Improvement 
Association is made thru the Seed Department of the Farm Bureau 
or directly by growers. The secretary of the Michigan Crop Im- 
provement Association (A. L. Bibbins, extension specialist) is there- 
fore left free to devote his energies to the proper development of the 
association, to registration and inspection of seed, etc. This plan 
greatly enlarges the demand for improved varieties and places quan- 
tity sale in the hands of a specially created department, properly 
equipped with machinery for cleaning and shipping. 

Briefly outlined, the plan for accomplishing the development, test- 
ing, increasing under inspection, and sale of seed of improved varie- 
ties in Michigan is as follows : — 

1. The Michigan Agricultural College, Farm Crops Department, 
Experiment Station and Extension: 

a. Varietal testing. Extensive varietal tests of all major crops, in- 
cluding standard and new varieties, are maintained at the experiment 
stations at East Lansing and Chatham, and also at numerous points 
over the State on a cooperative basis. 

b. Plant breeding. Pure-line selection and hybridization work with 
practically all crops adapted to Michigan. The following varieties as 
listed by Prof. F. A. Spragg have been contributed by the plant- 
breeding work during the past ten years: Worthy oats, 191 1 ; Rosen 
rye, 1912 ; Red Rock wheat, 1913; Michigan Winter barley, 1914; 
Robust beans, 191 5; College Wonder and College Success oats, 1916; 
Wolverine oats, 1917 ; Michigan 2-Row and Michigan Black barley, 
1918; and Michigan hardy alfalfa, 1919. 

c. Corn improvement. The local adaptation of varieties is estab- 
lished by varietal tests. Field selection and intensified selection by 
the ear-row method is carried on at the experiment station and at 
points over the State with leading varieties. In lower Michigan coun- 
ties the Duncan, Silver King, Early Reid and Learning are standard 
varieties; in central Michigan the Golden Glow and Pickett, and in 
northern Michigan the early Golden Glow and Early Pickett. 



84 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



d. Large increase fields on the station farm make possible rapid 
and safe distribution. Properly handled increase fields are highly 
important in securing effective distribution of new varieties. 

e. Extension specialists and county agents aid in securing wide- 
spread use of varieties of proved worth. 

2. The Michigan Crop Improvement Association (Secretary's 
Office, East Lansing, Mich.), an organization of farmers who are in- 
terested in crop improvement thru growing better varieties and the 
use of better cultural methods. A number are interested in the com- 
mercial production of high-grade seed. The association functions as 
follows : 

a. Seed of improved varieties is distributed to members from the 
Farm Crops Department increase plats* 

b. Record of distribution and transfer of varieties kept by the Sec- 
retary. 

c. Field inspection and thrashed grain inspection supported by the 
association under the leadership of the Farm Crops Department. 

d. Certification of seed which attains the high standards required 
is made by the Certification Committee. Certification is based on re- 
ports submitted by inspectors. 

3. The Michigan Farm Bureau Seed Department (Headquarters 
at Lansing, Mich.). This organization is authorized to sell certified 
seed produced by the Michigan Crop Improvement Association. 

a. A central warehouse has been established in Lansing fully 
equipped with adequate seed cleaning apparatus. A service charge 
is made for seed handled. 

b. County Seed Departments, under the direction of the State Seed 
Department, have been formed in 32 counties, and are being organized 
rapidly in remaining counties. 

c. In addition to the seed produced by the Crop Improvement As- 
sociation, the Farm Pmreau Seed Department also arranges for the 
purchase direct from growers of northern-grown alfalfa seed and for 
the extensive sale both in and out of the State of Michigan-grown 
clover, vetch, peas, beans, etc. 

This new development in the field of seed distribution is proving to 
be a marked step forward in securng the widespread use of high 

yielding varieties of adapted crops over large areas. The standard- 

zatiOfl of Crop production along proper lines is being followed by a 
• ticeable improvement in market quality. 



AGRONOMIC AFFAIRS. 



85 



AGRONOMIC AFFAIRS. 
THE SYMPOSIUM ON AGRONOMIC TEACHING. 

The program of the annual meeting of the American Society of 
Agronomy at Springfield, Mass., in October. 1920, consisted of sym- 
posia on two subjects, agronomic teaching and liming. The six papers 
which made up the first of these symposia are printed in this issue. 
Those on liming will follow in early issues, after which the papers 
included in the symposium on corn improvement at the December 
meeting of the Society in Chicago will be published. On several 
previous occasions, papers on teaching soils and crops have been 
printed in the Journal, but never before has so much material on 
this subject been brought together in a single issue. No more impor- 
tant subject can be considered by agronomists, for it involves not only 
the training of our agricultural college graduates who are to be our 
farm leaders in coming years, but of our future investigators and 
teachers of agronomy. Such papers as those printed in this issue 
form the best evidence of the usefulness of the American Society of 
Agronomy. 

MEMBERSHIP CHANGES. 

The membership reported in the January Journal was 551. Since 
that report was written the Society has enjoyed a healthy growth, and 
it is particularly encouraging to report that of the 81 members then 
reported as lapsed 15 have been reinstated. In nearly every case, 
these men have paid both 1920 and 192 1 dues. During the month. 6 
resignations have been received and 3 names not previously included 
in the lapsed list have been reported, while 25 new members have 
been recorded. These changes make a net increase of 31 and a total 
membership of 582. 

THE CHICAGO MEETING. 

A special meeting of the American Society of Agronomy was held 
in the Botany Building of the University of Chicago on the thirteenth 
anniversary of the founding of the Society, December 31. 1920, in 
connection with the meeting of the American Association for the Ad- 
vancement of Science. The program was a symposium on the subject, 



86 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



" Our Present Knowledge of Methods of Corn Breeding," prepared 
under the leadership of Prof. H. K. Hayes of the University of 
Minnesota. On the previous afternoon, the Society united in a joint 
session with the Botanical Society of America and the American 
Phytopathological Society. The programs of the two meetings 
follow. 

Joint Session, Thursday, December 30, 2.00 p. m. 

Recent Investigations on the Black Stem Rust of Wheat and Other Grains, 
by E. C. Stakman, Minn. Agr. Expt. Sta., St. Paul, Minn. 

Plants and Plant Culture, by C. V. Piper, Bureau of Plant Industry, Wash- 
ington. D. C. 

Natural Vegetation and Agriculture in Africa (illustrated), by H. L. Shantz, 
Bureau of Plant Industry, Washington, D. C. 

Friday, December 31, 0.00 a. m. 

The Experimental Basis for the Present Status of Corn Breeding, by F. D. 
Richer. Bureau of Plant Industry, Washington, D. C. 

The Bearing of Modern Genetic Studies on Corn Breeding, by R. A. Emer- 
son, Cornell University, Ithaca, N. Y. 

Corn Breeding as a Hobby, by H. A. Wallace, Wallaces' Farmer, Des 
Moines, Iowa. 

Progress Report on the Methods of Selection in Self-Fertilized Lines (illus- 
trated), by D. F. Jones, Conn. Agr. Expt. Sta., New Haven, Conn. 

Overcoming " Root-Rot " by Breeding, by W. D. Valleau, Kentucky Agr. 
Expt. Sta., Lexington, Ky. 

Friday, December 31, 2.00 p. m. 

Ear Type Selection and Yield in Corn (illustrated), by T. A. Kiesselbach, 
Neb. Agr. Expt. Sta., Lincoln, Neb. 

Progress Report on Corn Disease Investigations (illustrated), by James 
R. Holbert, Bureau of Plant Industry, Bloomington, 111. 

The Present Status of Continuous Selection Experiments with Corn, by 
L. H. Smith, Illinois Agr. Expt. Sta., Urbana, 111. 

Fir * Generation Varietal Crosses, by Fred Griffce, Minnesota Agr. Expt. 
St. 1 , St. Paul, Minn. 

Tlx- Relation <>i Weather to Rust Epidemics, by H. L. Walster, N. Dak. 
Agr. Expt Sta . Agricultural College, N. Dak. 

NOTES AND NEWS. 

l ; . ( /. Bamer, assistant agronomist at the Pennsylvania station, has 

resigned t f * engage j n commercial work. 

P, ( Bauer, who hai been engaged in graduate study at the Uni- 
versity of \\ 1- on^n, i- now extension agronomist in soils at the Uni- 
versity of Illinois. 



AGRONOMIC AFFAIRS. 



87 



R. K. Bonnett, formerly professor of farm crops, has been made 
professor of agronomy in the reorganization of the soils and crops 
work at the University of Idaho. G. R. McDole, formerly of the 
Minnesota college and station, and H. YY. Hulbert have been made 
assistant professors and F. L. Burkhart, field superintendent. 

T. S. Buie, formerly agronomist at the Georgia station, has been 
appointed specialist in fertilizer investigations at the Pee Dee Sub- 
station, Florence, S. C. 

A. C. Dillman, for the past several years engaged in forage-crop 
breeding in the office of alkali and drought-resistant plant-breeding 
investigations of the Federal Department of Agriculture, has been 
transferred to the office of cereal investigations and placed in charge 
of the flax project. 

P. L. Gaddis, professor of agronomy and agronomist at the Ne- 
braska college and station, has resigned to take charge of a farm in 
Custer Co., Nebr. 

Ralph Kenney, formerly extension agronomist at the Kansas col- 
lege, is now extension specialist in agronomy at the University of 
Kentucky. 

C. Larsen, director of extension in South Dakota, has been given a 
year's leave of absence to become director of the dairy products mar- 
keting department of the Illinois Agricultural Association. W. F. 
Kumlein, county agent leader, will be acting director of extension. 

E. F. Ladd, president of the North Dakota college, was elected to 
the United States Senate at the November elections. 

K. C. Livermore, professor of farm management at Cornell Uni- 
versity, has been granted a year's leave of absence to engage in 
farming. 

R. B. Lowry is now instructor in soils at the University of Ten- 
nessee. 

Fred G. Merkel has resigned his position at the Massachusetts sta- 
tion to become assistant professor of soil technology in the Pennsyl- 
vania college. 

P. H. Rolfs, for the past several years director of the Florida sta- 
tion, resigned December 31 to accept a commission to locate, estab- 
lish, and conduct an agricultural institution in the State of Minas 
Geraes, Brazil. The president of the State desires that the heads of 
all departments shall be American scientists. 



ss 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



R. E. Stephenson is now assistant soil chemist at the West Vir- 
ginia station. 

W. W. Weir, formerly assistant professor of soils in the Uni- 
versity of Wisconsin, is now editorial manager for the Soil Improve- 
ment Committee of the National Fertilizer Association. 

D. C. Wimer, formerly assistant professor of soil technology in 
the Pennsylvania college, has resigned to accept a position along sim- 
ilar lines in the University of Illinois. 

The agricultural building at the Alabama Polytechnic Institute at 
Auburn was entirely destroyed by fire on October 17. Included in 
the property burned were the college and station library and some 
valuable botanical collections. 

The National Academy of Sciences and the National Research 
Council have obtained a site for their new building in Washington, 
for which funds have already been donated. It will face the new 
Lincoln Memorial when erected, the site just purchased at a cost of 
about $200,000 being the block between B and C streets and 21st and 
22d streets northwest. The funds for the purchase were obtained 
from contributions made by a large number of persons. 

Science contains an interesting statement of doctorates conferred 
by American universities in 1920, with tabulations showing the num- 
ber of such degrees conferred by each university, the subjects in 
which the degrees were granted, and other information, including the 
names of those receiving the degrees and the titles of the theses. Of 
the 328 doctorate degrees granted in 1920, the University of Chicago 
leads with 59, followed by Cornell University with 35, Harvard with 
28, and 28 other institutions with smaller numbers. When classified 
according to subjects, chemistry is far in the lead, with 96, botany 
ranking second with 47. In agriculture, 8 doctorate degrees were 
conferred, 3 each by Cornell and Wisconsin and 1 each by Illinois 
and Minnesota. The recipients of the doctorate degrees in agricul- 
ture were: From Cornell University, Roy Glen Wiggans, Daniel. 

tl Fox, Frank App; from the University of Illinois, Jose J, 
Mirasol; from the University of Minnesota. Paul llarmer; from the 
University of YYi^'onsin, Win. Merriott (iibbs, Tsunao Inomato, 
Frederick C. Rauer. 

I 

■ H 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. March, 1921. No. 3 



THE SYMPOSIUM ON LIMING. 1 

C. V. Piper. 

The effects of liming in relation to soil quality and crop yields are 
varied and complex, a matter that needs to be borne in mind con- 
stantly when interpreting the results of experiments or field trials. 
The statement most commonly used in farm articles is that lime 
" sweetens the soil," a phrase that is alluring and probably overem- 
phasizes only one effect of lime. It is well to remember that lime- 
stone soils are proverbially rich, but there are exceptions, as in the 
chalk soils. The papers presented in the symposium did not cover 
all of the phases of lime in relation to soil changes and crop yields and 
it therefore seems desirable to introduce the papers with a brief syn- 
opsis of the definitely known facts and the more or less controversial 
problems in regard to the agricultural use of lime. These may be 
presented in a series of statements with brief comments. 

1. Lime is a necessary element of food to all plants but some kinds 
utilize it in much larger proportion than others. Some species, 
like alfalfa, red clover, and beets, seem to require larger amounts 
than others in their physiological processes. For certain other plants 
like rhododendrons too much lime is deleterious. On the basis of 
their normal relation to lime content of soil, botanists have classed 
plants as calciphiles or lime-lovers and as calciphobes or calcifuges or 
lime-haters. Many species however seem relatively indifferent. 
There is yet doubt as to whether these evident relations and reactions 

1 This brief introduction to the series of papers on liming presented at the 
thirteenth annual meeting of the American Society of Agronomy, Springfield, 
Mass., October 19, 1920, has been prepared by the associate editor for crops, 
Prof. C. V. Piper, agrostologist in charge of the Office of Forage Crop In- 
vestigations, U. S. Department of Agriculture, Washington, D. C. 

89 



90 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



are quantitative with respect to lime or qualitative in regard to toxicity 
or acidity. This phase of lime relations was not specifically presented 
in the symposium. 

2. Lime changes the reaction of the soil with reference to " acid- 
ity " and toxicity, and these affect favorably the yield of most but not 
all crops. Several papers discuss this relation of lime. 

3. Lime accelerates the process of nitrification especially by free- 
living organisms. The increased amounts of nitrates formed betters 
the yield of most crop plants, and this effect must needs be differ- 
entiated from other factors associated with lime. This function of 
lime is stressed in some of the papers. Additional information, how- 
ever, is needed in regard to possible long-time effects of continued 
liming on the nitrogen and humus content of a soil. 

4. Lime affects various chemical reactions of the mineral constitu- 
ents of the soil, thus changing their solubilities. One paper relates 
to these phenomena. 

5. Lime modifies the physical texture of the soil, a subject not dis- 
cussed specifically. In considering this effect of lime it is well to bear 
in mind that 1 ton per acre is less than 1 ounce to a square foot of 
surface. The flocculating effect of lime on clays is well established, 
[ts Mipposed binding effect on sandy soils is not definitely determined. 
Also the indirect effects of liming by increasing crop residues, espe- 
cially of clovers and grasses, together with increased liberation of 
( ',( )_., materially affect soil structure. 

6. Lime modifies the abundance of some parasitic fungi. In some 
cases the disease is prevented or minimized, as in club root of cru- 
ciferous plants; in others it is accentuated, as in potato scab. This 
was not considered in any of the papers. 

7. Loew's contention that a particular ratio of lime to magnesia is 
important for most crop plants is still a subject of controversy. One 
paper deals more or less directly with this subject. 

8. The effects of lime in practical use vary both with the physical 
and chemical natures of the calcareous material used. Three of the 
papers are devoted to phases of these effects. 



1 



TRUE THE FUNCTION OF CALCIUM. 



91 



THE FUNCTION OF CALCIUM IN THE NUTRITION OF 
SEEDLINGS. 1 

Rodney H. True. 2 
Limits of the Paper. 

In the beginning of this discussion I wish to call attention to the 
limits which bound it. It deals with seedlings of various crop plants 
grown in water cultures which were usually kept in darkness when 
not under observation. However, in several cases similar experi- 
ments carried on in the light gave results essentially similar to those 
seen in experiments carried on in darkness. The methods used, the 
sources and the magnitude of recognized errors are not dealt with, 
having been discussed previously elsewhere. 3 

The principles developed here are applied with caution to plants 
not studied, as unexpected specific and racial peculiarities have been 
found. This paper presents only results of work in which the writer 
has been directly concerned, usually in association with colleagues, 
and no attempt is made to review the work of others. 

THE PROBLEM STATED. 

The results here reported have come from an attempt to ascertain 
more clearly the nature of the indispensable work done in green 

1 Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 19, 1920. Contribution from the Uni- 
versity of Pennsylvania, Philadelphia, Pa. The observations here recorded 
were made while the writer was employed in the Bureau of Plant Industry, 
United States Department of Agriculture, as physiologist in charge of Plant 
Physiological Investigations. The formulation of these results has been made 
since his transfer to the University of Pennsylvania. 

2 Professor of botany and director of the botanical garden, University of 
Pennsylvania, Philadelphia, Pa. 

3 True, Rodney H. and Bartlett, Harley Harris. Absorption and excretion 
of salts by roots, as influenced by concentration and composition of culture 
solutions. I. Concentration relations of dilute solutions of calcium and mag- 
nesium nitrates to pea roots. U. S. Dept. Agr., Bur. Plant Indus. Bui. 231. 
1912. 

True, Rodney H. The harmful action of distilled water. In Amer. Jour. 
Bot, 1 : 255-273. 1914. 

True. Rodney H. and Bartlett, Harley Harris. The exchange of ions be- 
tween the roots of Lupinus albus and culture solutions containing one nutrient 
salt. In Amer. Jour. Bot., 2: 255-278. 1915. 



92 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



plants by calcium in the most commonly utilized combinations, and 
thus to learn why land must contain lime or some other compound 
containing the calcium ion. The writer realizes the great reach of 
the problem and contributes this as a report of progress. 

METHODS USED. 

Seedlings of crop plants obtained by germinating the seeds in clean 
sphagnum were grown in beakers of slowly soluble glass containing 
culture solutions made up with carefully prepared distilled water 
which was usually made in a laboratory containing no gas, in which 
heat was obtained from electric heating coils. Culture solutions were 
made up with the best salts obtainable purified by further treatment 
when it seemed necessary. The concentration of these solutions dur- 
ing experiments was measured by the resistance offered to the pas- 
sage of the electric current measured by the usual telephone method. 
Considerable changes in concentration were assumed to be due to the 
taking in or giving out of ions by seedlings. The duration of an ex- 
periment was determined by the food reserve in the seed. 

Seedlings in Distilled Water. 

When lupine seedlings are grown in distilled water the following 
result appears with considerable regularity. During the first period, 
lasting from 4 to 6 days, the distilled water increases steadily in con- 
centration due to the giving off of ions to the solution by the roots of 
tlx- plants. It is likely that these ions are in part due to the C0 2 
given "ft" by the respiring seedlings. These saturate the solution, 
which finally reaches a concentration in equilibrium with the C0 2 
content of the air. After this initial period, the concentration of the 
distilled water usually continues approximately the same with minor 
changes until the seedlings begin to deteriorate. Then the tissues 
apparently become more permeable, or interior breakdown liberates 
a greater quantity of ions which pass into the solution. The concen- 
tralion then -how s a decided increase which grows as injury involves 

additional cells. 

Si 1 DLINGI IN RlVEU Water. 

\s ordinary river water is a good culture medium for seedlings, 
were carried out in water from the Potomac River. 4 At the 

'Composition Oi Potomac River water, as determined by Outwater, is re- 
ported by Parker, II. V. W illis, liailcy, Bolster, R. II., Ashe, W. W., and 
Marsh, If ( 'Mm- Potomac River I'.asin. Water Supply and Irrigation Paper 
192: 297. U. S. Geol. Survey 1907. 



TRUE THE FUNCTION OF CALCIUM. 



93 



time these samples were taken this water had a usual composition 
which gave a resistance corresponding to a 37X X io~ 4 solution of 
KC1. From the day on which the seedlings were placed in it, the 
concentration rapidly decreased on account of the active absorption 
of ions by the roots of the seedlings. This continued until the con- 
centration of the river water fell below that at which an equilibrium 
is reached in distilled water. In the mixture of ions contained in 
Potomac water absorption exceeded leaching to such an extent that 
at the end of the experiment the river water contained approximately 
as many ions as a good (but not excellent) grade of distilled water. 

Seedlings in Cane-Sugar Solutions. 

In order to ascertain whether the difference in the behavior of the 
seedlings observed in distilled water and in Potomac water was due 
to the osmotic properties of the dissolved material present in. the 
latter, solutions of cane sugar were made up in distilled water with 
an osmotic value equal to that of the river water. Seedlings placed 
in the sugar solutions behaved essentially like those in distilled water. 
The ions given off to the medium greatly exceeded in quantity the 
number that might possibly have been absorbed. It appears clear, 
therefore, that Potomac water differed from distilled water in its 
essential physiological properties because of the inherent nature of 
the dissolved material rather than because of the mere fact of the 
number of ions and molecules present. 

Seedlings of Lupinus albus in Solutions Containing Single Salts. 

Since it appeared that the behavior of seedlings in these solutions 
depended on the chemical qualities of the ions present, a series of 
experiments was carried out in which the ions commonly recognized 
as essential to plant development were dissolved in distilled water. 
The concentrations offered to the seedlings usually ranged from a 
very small ion content 18 to 20 gm. normal in a million liters) to 
that ordinarily reached in the soil solution of a rainy climate (200 to 
500 gm. normal in a million liters). 

I. POTASSIUM SALTS. 

In solutions containing potassium salts, seedlings of the white lupine 
(Lupinus albus) behaved very much as they did in distilled water 
and rarely made a net absorption. 

In Table 1 are shown the original concentrations of potassium- 
containing solutions offered to the seedlings, the concentration of 



94 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



these solutions at the time when absorption was greatest, and the day 
on which maximum absorption was noted. 



Table r. — Absorption by seedlings in solutions of potassium salts. 



Salt. 


Original concen- 
tration 

(N X io-6). 


Concentration 
at time of maxi- 
mum absorp- 
tion (N X io-6). 


Absorption or 
leacn ^rs X'o 


Day of maxi- 
mum absorption. 


KC1 


32 


101 


— 79 


nth 




96 


152 


-56 


10th 




160 


210 


-50 


9th 




224 


272 


-48 


1 2th 




288 


302 


— 14 


14th 




352 


39 1 


— 39 


10th 




416 


442 


-26 


14th 


Distilled water 


O 


80 


-80 


14th 


K*S0 4 


20 


32 


— 12 


nth 




60 


68 


— 8 


12th 




100 


107 


— 7 


nth 




l6o 


160 





nth 




200 


192 


+ 8 


nth 




240 


242 


— 2 


nth 


Distilled water 





17 


— 17 


12th 


KH2PO4 


32 


108 


-76 


10th 


(Calculations assume ioniza- 


64 


128 


-64 


15th 


tion into K and H2PO4 ions.) 


96 


144 


-48 


12th 




176 


204 


-28 


10th 




208 


300 


-92 


13th 


Distilled water 





87 


-87 


15th 


K NOi 


32 


101 


-69 


1 6th 




96 


155 


-59 


13th 




160 


188 


-28 


13th 




224 


207 


+ 17 


14th 




288 


272 


+ 16. 


15th 




352 


339 


+ 13 


1 2th 




416 


423 


*" 7 


14th 


Distilled water 


«) 


80 


-80 


15th 



The rate of absorption seemed to be greatest after the tenth day 
shortly before the deterioration of the seedlings set in. A very slight 
nei ah option U as registered in stronger solutions of 1\.,S( ), and in 
KN0 8 , but in no ease did it become greater than about 13N X 10~ 9 j 
a quantity ranging in magnitude with the quantity of ions likely to be 
found in good distilled water. It is also to be noted that absorption 
nrai distinctly greater in the nitrate series than in any other. 

2. MA(,\I.SMM SALTS. 

Similar Culture! were set up in solutions containing magnesium 
ioilS. Here, two new features appeared. After a (lay's loss of ions, 
• ■ "-dlnu' began to make a marked absorption which continued 



TRUE THE FUNCTION OF CALCIUM. 



95 



for several days before deterioration occasioned a rapid leakage of 
ions. In some of the more concentrated solutions injury and leakage 
began to appear several days earlier than was usual in other cultures. 
Table 2 shows a part of the data. 



Table 2. — Absorption by seedlings of white lupine in solutions of 
magnesium salts. 



Salt. 


Original concen- 
tration 
(NX«r*). 


Concentration 
at time of maxi- 
mum absorp- 
tion (NX 10-6). 


Absorption or 
leach (NXio -s). 


Day of maxi- 
mum absorption. 


MgSO* 


12 


26 


-14 


I3th 




60 


48 


+ 12 


I3th 




96 


83 


+ 13 


10th 




144 


134 


+ 10 


8th 




16S 


153 


+15 


7th 


Distilled water 


O 


18 


-X8 


io-i3th 


Mg(N0 3 ) 2 


8 


10 




13th 




32 


9 


+23 


13th 




64 


45 


+ 19 


nth 




104 


94 


+ 10 


10th 


Distilled water 





10 


— 10 


nth 



The tendency of the seedlings to absorb more from the nitrate 
solution than from others noted in the case of the potassium series is 
again seen. 

3. CALCIUM SALTS. 

Cultures containing calcium salts showed active absorption in all 
concentrations except from those so dilute that the unavailable mini- 
mum was soon reached. Data are given in Table 3. 

CONCLUSIONS. 

Certain definite results seemed to come from these experiments 
with white lupines in solutions of single salts. 

(1) Since in solutions of but one K-containing salt absorption of 

electrolytes equals loss, it appears clear that the K ion is not ab- 
sorbed in considerable quantity. 

(2) When the K ion is accompanied by the NO a anion, absorption 
slightly exceeds loss in a number of the higher concentrations. 

(3) When the K ion is accompanied by the S0 4 ion and by the 

H 2 P0 4 ion, leach greatly exceeds absorption. Since the behavior of 
KH 2 P0 4 in the solutions here given may not be accurately repre- 
sented in our calculations it is quite possible that the facts are not 
correctly presented here. However, the main fact just stated seems 
to be plain. 



96 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

(4) Solutions of magnesium salts are clearly absorbed, whether 

the Mg ions are accompanied by N0 3 ions or by S0 4 ions. This ab- 
sorption tho well defined in all except the most highly dilute solu- 
tions is limited and injury to the seedlings soon appears. Mg ions 
altho absorbed seem to be toxic even when much diluted. 

(5) Solutions containing calcium compounds are actively absorbed 

by the white lupine whether the Ca ions be accompanied by S0 4 or 

N0 3 anions. The Ca ion seems to be chiefly responsible for this ab- 
sorption. 



Table 3. — Absorption by seedlings of white lupine in solutions of calcium salts. 



Salt. 


Original concen- 
tration 
(NX 10-6). 


Concentration 
at time of max- 
imum absorption 
(NX 10-6 ). 


Absorption or 
leach (NXio-«). 


Day of maxi- 
mum absorption 


CaSC>4 


12 


II 


+ I 


1 2th 




60 


1 1 


+49 


I5th 




84 


33 


+Si 


14th 




120 


76 


+44 


15th 




168 


116 


+52 


16th 







14 


-14 


7th 


Ca(N0 3 ) 2 


8 


S 


+ 3 


I0-I2th 




16 


5 


+ 11 


14th 




48 


17 


+3i 


12th 




56 


32 


+24 


14th 




96 


59 


+37 


13th 


Distilled water 





12 


— 12 


1 2th 


Ca(NO,) 2 


20 


13 


+ 7 


I0-I2th 




60 


30 


+30 


I5th' 




100 


50 


+ 50 


14th 




160 


97 


+63 


15th 




220 


130 


+90 


15th 




240 


182 


+58 


13th 


Distilled water 





33 


-33 


15th 



ACIIl LAND PLANTS AND NON-ACID LAND PLANTS. 

Experiments carried out with various crop plants show that the 
lupine ifl fairly representative of a group associated in practice with 
sandy, usually acid lands. To this group belong the peanut, white 
dent Indian corn, and alsike clover. 

Contrasted with this group is another characteristic of richer soils 
which usually contain a greater proportion of lime. To this group 
belong the squash, soybean, red clover, and apparently the sweet corn 
of the gardens. 



TRUE THE FUNCTION OF CALCIUM. 



97 



Squash Seedlings in Solutions of Calcium Salts. 

Squash seedlings showed marked differences in behavior in dif- 
ferent solutions of calcium salts, apparently being strongly influenced 

by the anion as well as by the Ca ion. CaCl 2 , CaCO s , and Ca(NO s ) 2 
were absorbed in similar degree by squashes. CaS0 4 to a much less 
extent. This situation is illustrated by Table 4. made from data 
worked out in large part by Dr. Rodney B. Harvey. 5 



Table 4. — Absorption by seedlings of Early Prolific Marrow squash in calcium 

solutions. 



Salt. 


Original con- 
centration 
(NX 10-6). 


Concentration 
at time of maxi- 
mum absorption 
(NX 10-6). 


Absorption 

or leach 
(NX 10-6). 


Ca(N0 3 ) 2 


24-5 


34-0 


- 9-5 




63.0 


34-6 


28.4 




96.3 


34-0 


62.3 




182.6 


29.6 


153-0 




351-8 


39-1 


312.7 




518.5 


47-8 


470.7 




693-5 


125-9 


567.6 




867.0 


152.9 


714-1 


Distilled water 


1 1.7 


50.0 


-38.3 


CaCh 


15-7 


26.5 


— 10.8 




75-3 


20.5 


54-8 




116. 5 


19.7 


96.8 




384-0 


32.3 


351-7 




582.4 


141. 1 


441.4 




8.0 


45-0 


-37-0 


Ca SO4. . 


15-6 


50.0 


-34-4 




52.1 


377 


14.4 




IOI.Q 


76.0 


25-9 




3I9.I 


251-5 


57-6 




535-4 


448.1 


87-3 




824.4 


704.6 


119.8 


Distilled water 


10. 


45-0 


-35-0 



It will be noted that absorption from the nitrate and chlorid solu- 
tions increases with the concentration offered, the unused surplus re- 
maining relatively small, while in the case of the sulfate the reverse 
is seen, the unused surplus increasing as the quantity offered in- 
creases. The S0 4 ion seems to be clearly responsible for this result. 

Let us now compare the behavior of the white lupine with that of 
the squash. We see that while absorption from both calcium-con- 
taining solutions is relatively small in the case of the lupine, absorp- 
tion from the Ca(N0 3 ) 2 solution is approximately like that from the 

5 True, R. H., and Harvey, R. B. Absorption of calcium salts by squash 
seedlings. In Brooklyn Bot. Garden Memoirs, 1: 502-512. 1918. 



9 8 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



CaS0 4 solutions. With the squash, absorption from the CaS0 4 solu- 
tion is roughly the same in quantity as that seen in the lupine. When 

however the Ca ion is accompanied by either the CI or the N0 3 anion, 
absorption is very much greater. 

In this connection it should be noted that the lupine is an acid-loving 
plant of the most pronounced type grown usually on thin sandy soils 
in which the soil solution may be expected to be distinctly poor in the 
nutrient ions and perhaps rather dilute under usual weather condi- 
tions. The squash, however, is a garden plant grown best in rich 
soils in which the soil solution is likely to carry much more material, 
including sufficient calcium. 

Similar experiments carried out with several species of plants 
seem to show that these plants are representative of two strongly 
marked physiological types. Acid-land crops like the white lupine, 
field corn (Boone County White), alsike clover, and peanuts ab- 
sorbed relatively sparingly from all Ca-containing simple solutions 
and took up approximately as much from the sulfate solutions as 
from the nitrate solutions. Garden plants and field crops requiring 
rich soils were found to absorb much greater quantities from calcium 

solutions than the other group, except when the Ca ion was accom- 
panied by the S0 4 ion. To this group of strong-feeding Ca-loving 
plants belong the marrowfat squash, soybean, red clover, and sweet 
corn (Country Gentleman?). 

Seedlings op Lupin us albus in Solutions Containing Two Salts. 

In view of the fact that in nature plants that succeed in living must 
absorb more than they lose and must absorb ions that are not taken 
Up from these simple solutions it seemed likely that the behavior of 
plants toward these ions might be modified by the presence of still 
others. We have already seen evidence pointing in this direction in 

the marked influence of the presence of the S0 4 ion on the absorp- 
tion from calcium-containing solutions. 

Consequently solutions of nutrient salts were prepared in which 
different pairs of salts were mixed. Seedlings of Lupinus albus 
were used. It has been shown in the above experiments with single 
salts that both kations and anions exert a pronounced influence on 
BbfeOfption, It was desired first to study especially the seedlings of 
the K, M'/. and Ca ions, and in order to stabilize the influence of the 
anions as much as possible, nitrates were used in all cases. 



TRUE THE FUNCTION OF CALCIUM. 



99 



I. MIXTURES OF CA<NQk)« AND KX0 3 . 

Four groups of mixtures were prepared ranging in total salt eon- 
tent from 120 to 480 gram-normal in a million liters. In each group 
were five solutions in which the salts named appeared in the fol- 
lowing proportions: % KNO s ; % KNO s , % Ca(N0 3 ) ; % KXO s , 
% Ca(NO s ) 2 ; % KN0 3 , % Ca(N0 3 ) 2 ; and % Ca(NO s ) 2 . In Table 
5 are shown for each mixture (i) the original concentration, (2) 
concentration at time of maximum absorption, and (3) quantity ab- 
sorbed or leached out at that time. 



Table 5. — Concentration changes caused by white lupine seedlings in mixtures 
ofKXO,andCa(X0 3 ) 2 . 



Solution. 


Original 
concentra- 
tion 
( JN Xio *). 


Concentra- 
tion at time 
of maximum 
absorption 
(NX«r«). 


Absorption 

or leach 
(NXior«). 


Day of 
maximum 
absorption. 


4/4 KNO3 


120 


132 


— 12 


10 


3/4 KNO3 1/4 Ca(N0 3 )2 


120 


98 


22 


10 


2/4 KNOs 2/4 Ca(N0 3 ) 2 


120 


86 


34 


II 


1/4 KNO3 3/4 Ca(N0 3 )2 


120 


• 66 


54 


12 


4/4 Ca(NOs)2 • 


120 


68 


52 


12 


Distilled water 





25 


-25 


10 


4/4 KNO3 


240 


274 


-34 


II 


3/4 KNOs 1/4 Ca(N0 3 ) 2 


240 


173 


67 


14 


2/4 KNO3 2/4 Ca(N0 3 )2 


240 


167 


73 


12 


1/4 KNOs 3/4 Ca(N0 3 )2 


240 


133 


107 


14 


4/4 Ca(NO«)j 


240 


185 


55 


II 


4/4 KNOs 


360 


368 


- 8 


7 


3/4 KNO3 1/4 Ca(NOs)2. 


360 


291 


69 


11 


2/4 KNOs 2/4 Ca(NOi)j 


360 


258 


102 


. 14 


1/4 KNO3 3/4 Ca(X0 3 )2 


300 


202 


158 


14 


4/4 Ca(N0 3 ) 2 


360 


288 


72 


9-1 1 


4/4 KNOs 


480 


463 


17 


11 


3/4 KNO3 1/4 Ca(N0 3 ) 2 


480 


370 


no 


11 


2/4 KNO3 2/4 Ca(N0 3 ) 2 


480 


348 


132 


12 


1/4 KNO3 3/4 Ca(N0 3 ) 2 


480 


342 


138 


14 


4/4 Ca(N0 3 ) 2 


480 


384 


• 96 


10-12 



Certain general results appear to be clearly marked. (1) Absorp- 
tion from the simple solutions tends to become greater as the con- 
centration of the solution increases. (2) Absorption from mixtures 
is always greater as the proportion of Ca(N0 3 ) 2 in the mixtures in- 
creases, the most favorable ratio in all total concentrations being 
% KN0 3 , % Ca(X0 3 ) 2 . This is equivalent to saying that while 
KN0 3 alone can not be absorbed by white lupine seedlings under 
the conditions here seen, a greater quantity of ions is absorbed from 
the mixture because a small proportion of KNO s is present. 



100 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



In but one instance (240N X icr 6 Y\ KNO s , l /x CaNO s ) was the 
absorption equal to the quantity of Ca(N0 3 ) 2 put into the solu- 
tion when it was made up. It is therefore impossible to say that the 

presence of the Ca ion has caused the absorption of the KNO s , since 
the total absorption might possibly have come from the Ca(N0 3 ) 2 
component. On the other hand the fact that absorption is greatly in- 
creased and sometimes nearly doubled when % of the Ca(N0 3 ) 2 is 
replaced by an equivalent quantity of KNO s argues strongly for an 
absorption of the latter component. 

2. MIXTURES OF MC.(n0 3 ) 2 AND KN0 3 . 

Mixtures of Mg(N0 3 ) 2 and KN0 3 similar to those just noticed 
were prepared and planted with lupine seedlings. The results of 
this experiment are shown in Table 6. 



Table 6. — Concentration changes caused by Lupinus albus seedlings in mixtures 
of Mg(NO*) 2 and KNO,. 



Solution. 


Original 
concentra- 
tion 
(NX 10-6). 


Concentra- 
t on at time 
of maximum 
absorption 
(NX»i. 


Absorption 

or leach 
(NX 10-6). 


Day of 
maximum 
absorption. 


4/4 KNOi 


120 


137 


-17 


6 


3/4 KNOj 1/4 Mg(NOi)s 


I20 


105 


15 


8-10 


2 4 KNOj 2/4 Mg(NO$)i 


I20 


98 


22 


8 


i '4 KNOj 3/4 Mg(NOi)i 


120 


88 


32 


10 


4/4 Mg(N0 3 ) 2 


120 


83 


37 


9-10 




O 


28 


-28 


8 


4/4 KNOs 


240 


240 





7-8 


3 4 KXOj 1 4 M(j(\()j)2 


240 


196 


44 


11 


2/4 KNOi 2 4 Mg(NOj)! 


24O 


218 


22 


8 


1/4 KNOi 3/4 Mg(NOi)i 


240 


193 


47 


12 


4/4 Mg(NO,) 2 


240 


208 


32 


10-1 1 


4/4 KNOi 


360 


357 


3 


8 


3 4 KNOi 1/4 Mg(NOi), 


360 


324 


36 


8 


2 ; K.VO, 2/4 Mg(NO|)f. 


300 


325 


35 


13 


1 4 KNO, 3/4 Mg(NOi)i 


300 


333 


27 


7-8 


4/4 M K (NO»)j 


36O 


357 


3 


3 


4/4 KNOi 


480 


470 


10 


8 


\ 1 KNO, 1 M K (NOa), 


480 


45i 


29 


8 


2/4 KNO, 2/4 MgfNO,), 


480 


440 


40 


11-12 


1 4 KNO, V4 Mk^N'O,), 


480 


470 


10 


6-7 


4/4 Mff(NOi)i 


48O 


462 


18 


7 



1 It will be imtcd that while in the simple solutions of KN'D 3 
light tendency for net absorption to take place in the more 
concentrated lolutions, in the simple solutions of Mg(NO :t )._, the ab- 
sorption, while never very considerable, tends to become less as the 
ronrrnt ration is increased. 



TRUE THE FUNCTION OF CALCIUM. 



IOI 



2. In the mixtures a somewhat greater absorption is usually found 
than in the simple Mg(N0 3 ) 2 solution, but this difference is not 
very great, and no clearly favorable proportion appears. Thus the 

presence of the K ion may facilitate slightly the absorption of the 

Mg ion or vice versa. 

3. MIXTURES OF CA(n0 3 ); AXD Mg(NOj),. 

A third series of mixtures made up and tested in the above manner 
dealt with Ca(NO s ) 2 and Mg(N0 3 ) 2 . It will be noted however that 
proportions are so modified as to show the effect of small quantities 
of Ca(N0 3 ) 2 . The absorption data at the time of its maximum are 
shown in Table 7. 



Table 7. — Concentration changes caused by white lupine seedlings in mixtures 
of Ca(N0 3 ), and Mg{NOz),. 



Solution. 


Original 
concentra- 
tion 
(NX 10-6). 


Concentra- 
tion at time 
of maximum 
absorption 
(XX 10-6). 


Absorption 

or leach 
(XX 10-6). 


Day. 


4/4 Ca(X0 3 ) 2 


120 


53 


67 


16-17 


2/4 Ca(X0 3 ) 2 2/4 Mg(XC> 3 ) 2 


120 




68 


13-14 


1/4 Ca(X0 3 ) 2 3/4 Mg(NC> 3 ) 2 


120 


2 


70 


13 


1/10 Ca(N0 3 ) 2 9/10 Mg(X0 3 )2 


120 


72 


58 


12 


4/4 Mg(N0 3 ) 2 


120 


in 


9 


IO-I3 


4/4 Ca(N0 3 ) 2 


24O 


121 


119 


I6-I7 


2/4 Ca(N0 3 ) 2 2/4 Mg(X0 3 ) 2 


240 


126 


114 


15 


1/4 Ca(NOa)s 3/4 Mg(NOa)i 


240 


145 


95 


13 


1/10 Ca(N0 3 ) 2 9/10 Mg(NOa)a 


24O 


180 


60 


I5-I6 


4/4 Mg(NC> 3 ) 2 


240 


,35 


5 


9-12 


4/4 Ca(N0 3 ) 2 


36O 


203 


157 


18 


2/4 Ca(N0 3 ) 2 2/4 Mg(N0 3 ) 2 


300 


l60 


200 


17 


1/4 Ca(NOs) 2 3/4 Mg(NQa)i 


300 


237 


123 


17 


1/10 Ca(X0 3 ) 2 9/10 Mg(X0 3 ) 2 


36O 


233 


127 


I6-I7 


4/4 Mg(XC> 3 ) 2 


360 


350 


10 


10-12 


4/4 Ca(X0 3 ) 2 


48O 


293 


187 


I7-I8 


2/4 Ca(X0 3 ) 2 2/4 Mg(NOa)t 


48O 


284 


196 


l6-I7 


1/4 Ca(X0 3 ) 2 3/4 Mg(XOs) 2 


48O 


279 


201 


15-17 


1/10 Ca(X0 3 ) 2 9/10 Mg(XOs) 2 


48O 


315 




I6-I7 


4/4 Mg(X0 3 ) 2 


48O 


495 • 


-% 


5 



i. It seems to be generally true that in solutions of weak total con- 
centration absorption from unmixed Ca(N0 3 ) 2 solutions is almost 
as great as it is in mixtures containing a portion of Mg(N0 3 ) 2 . In 
the higher total concentration a clear tho not great increase comes 
with the presence in the solution of equal parts of the two salts. 



102 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



2. When the proportion of Ca(NO s ) 2 is further reduced, absorp- 
tion falls off when the proportion of Ca(N0 3 ) 2 to Mg(N0 3 ) 2 be- 
comes i to 9. 

3. It appears, however, that the presence of Ca aids the absorption 
of other ions since absorption is relatively much greater than the 

quantity of Ca ions present. In almost all cases, the quantity of 
ions absorbed is in excess of the quantity of the calcium put into 
the solution, and in the more dilute mixtures and those in which the 
proportion of Ca salt is small, it is much in excess. 

RESULTS IN NITRATE SOLUTIONS DISCUSSED. 

As a result of the experiment with pairs of nitrates it appears 

+ +• 

probable that the presence of Ca ions in mixtures with either potas- 
sium or magnesium nitrates secures an increased absorption of the 
ions of the latter salts. Such an interaction in mixtures of mag- 
nesium and potassium nitrates was not clearly seen. 

When the nitrates mentioned are offered in pairs in solutions vary- 
ing from 120N X io -6 to 480N X io -6 , the seedlings of the white 
lupine absorb more electrolytes than they do from unmixed solutions 
of the salts concerned. 

In mixtures of Ca(NO :{ ) 2 and KN0 3 , the deterrent action of K 
ions on absorption is seen in the high ratio of Ca to K required to 
give maximum absorption, viz, 3 Ca to 2 K. The value of a small 

quantity of K ions is however proved by the excess of absorption in 
a mixture containing them over that from a simple Ca(NO :{ ) 2 solu- 
tion. The absolute quantity of Ca present in the mixtures seems to 
be of great influence for, as the proportion of Ca increases in the di- 
lute solutions, absorption is increased. The favorable action of Ca 
ions is therefore striking in mixtures as well as in pure solutions. 

In mixtures of Ca(NO,) 2 and Mg(NO s ) 2 the greatest absorption 
was found in the ratios 2 Ca : 2 Mg or 1 Ca : 3 Mg. The great sig- 
nificance of even a small proportion of Ca is seen in a relatively high 
absorption made in a mixture containing 1 Ca to 9 Mg. 

In mixture, containing CafNO.,),, and KNO :t and in those con- 
taining rafXO.).. and MgfXO,)., it seems likely that the presence 
of the Ca ions increases the absorption by the seedlings of the ions of 
tli'- '.thrr salts i.e., Ca ions seem to aid the absorption of Mg and of 

K loni. Such an effect was not seen in the mixture containing 
M^NO,), and KNO,. 



TRUE THE FUNCTION OF CALCIUM. 



I03 



Seedlings of Lupinus albus in Solutions Containing Three Salts. 

It has been found practicable to bring crop plants to a fairly nor- 
mal maturity in three-salt mixtures to which a suitable source of 
iron has been added. Our next experiment was planned to test the 
effectiveness of more complicated mixtures but in such a way as to 
secure further data if possible on the influence of the commoner 

nutrient cations: Ca, Mg, and K. 

1. Salts with a Common Anion. 

Since anions electrically equivalent to the quantity of cations 
present should be found in the solution in order to avoid perplexing 
complications, and since by using one anion in equivalent quantity it 
seemed that we should be more likely to get a clear view of the action 
of the different cations, a series of solutions was made up in which 
Ca(N0 3 ) 2 , Mg(N0 3 ) 2 , and KN0 3 were mixed in all possible pro- 
portions. The result was a set of 36 cultures which when so ar- 
ranged filled out the well-known triangular scheme of the physical 
chemists and plant physiologists. 

Since the simple solutions occupying the vertices of the triangle 
and the mixtures of two salts which filled up the three sides fall into 
groups of experiments already considered, we shall consider here 
the fifteen " inside " mixtures in which all three salts were present. 
Moreover, since it seems hardly necessary to review all of these in 
detail, the most striking results may be briefly summarized (Table 8). 

Table 8. — Absorption by Lupinus albus seedlings from mixtures of two salts 
having a common anion (NOz). a 

Average maximum absorption of series. 
Solutions. N X 10 -6 . Percent. 

KNO3, Ca(N0 3 ) 2 44-i 310 

Mg(NO,)„ Ca(N0 3 ), 53-3 38.1 

KNO3, Mg(NOs) 2 22.2 15.8 

Average from 2-salt (3-ion) solutions 39.9 28.5 

a The total original concentration of each mixture was 140N X io -6 . 

In this and subsequent tables, percentages indicate the proportion of the 
original total number of ions that had been absorbed at the time of maximum 
absorption. 

The favorable action of the Ca is clearly shown here. 
The results seen in cultures containing three nitrate salts are shown 
in Table 9. 



104 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 9. — Absorption by Lupinus albus seedlings from solutions containing 

three nitrates. 

Maximum absorption. 





Solutions. 




IN X 'O D 




mo KNO 


20 Ca^NO,} 


20 Mo-CNO 


/I7 O 




80 KNOi, 




i>o Mp-CNO^L 


^8 8 


27 7 
■*/•/ 


fSo KNO 


60 CaCNO ") 


2f) McrCNO 1 


70 n 


i>o-4 


in KXO 


80 CaCNO ) 


20 Mp- C NO ^ 


60 4 






too fafNO.) 


20 Mo-CNO,") 


72 7 


CT O 






40 Mo-CNO,") 


20 "J 


20 9 


60 K\ t O 


ao CaCNO 

^KJ V^c* y IN V-/3 / o> 


40 Mp-CNOo^ 


71 A 




do KNO. 


60 CafNO.), 




78 7 


c6 2 


JO KNO3, 


80 Ca(N0 3 ) 2 , 


40 Mg(N0 3 ) 2 


A*7 Q 


"*zl 2 


60 KNO G , 


20 Ca(N0 3 ) 2 , 


60 Mg(NO,)-, 


AO 2 


^S* I 


40 KN0 3 , 


40 Ca(N0 3 ) 2 , 


60 Mg(N0 3 ) 2 


• • 51. 1 


36.5 


20 KNO s , 


60 Ca(N0 3 ) 2 , 


60 Mg(N0 3 ) 2 


.. 42.9 


30.7 


40 KNO3, 


20 Ca(N0 3 ) 2 , 


80 Mg(N0 3 ) 2 


46.8 


334 


20 KN0 3 , 


40 Ca(NO s ) 2 , 


80 Mg(N0 3 ) 2 


75-9 


54-2 


20 KNO3, 


20 Ca(N0 3 ) 2 , 


100 Mg(N0 3 ) 2 


■ • 52.5 


37-5 


Average absorption in 3-salt (4-ion) solutions.. 


56.3 


40.2 


Average absorption in 2-salt (3-ion) solutions.. 


•• 39-9 


28.5 



" The total original concentration of each solution was 140N X 10 6 . 
From these results it seems clear that the increase in the number 
of cations from two to three alone serves to increase very materially 
the quantity of ions absorbed by these plants even when the only 

anion present is the NO s ion. 



2. SALTS WITH DIFFERENT ANIONS. 

Similar three-salt mixtures were made up in which the three im- 
portant nutrient cations Ca, Mg, and K, were electrically balanced by 

the three necessary nutrient anions, NO :; , S0 4 , and P0 4 . A similar 
triangular experiment was set uj) with a scries of solutions having a 
constant total concentration of 140N X ICT 6 . 

Since new pair* of -alts occur in the experiment each carrying a 
different anion, it seems worth while again to summarize the data for 
these mixtures. This is done in Table to. 



T m i f 10. Absorption by Lupintu albus seedlings from mixtures of two salts 
Inn ing different anions." 

Average maximum absorption. 

Solution*. N X 'o 6 Percent. 

KHJ'O,. CafNO,), 00.5 64.7 

M*S0 4f Ca(NO,), 85.1 60.8 

MkSO,. KHJ'O 44.4 317 

\ tTWgt absorption from 2-salt (4-iotl) mixtures 73.3 52.4 

•The original total concentration <>f etch mixture is 140N x 10". 



TRUE THE FUNCTION OF CALCIUM. IO5 

By contrasting the absorption here seen with that given for 3-ion 
solutions (pairs of nitrates) in Table 8, the great increase due to the 
partial replacement of the NO s ions with others in equivalent quan- 
tity, the importance of these newly introduced ions may be readily 
seen. Again, anions associated with leach in solutions of single salts 
when brought into a mixture are seen to bring with them a marked 
increase in absorption. 

In Table 11 are shown the results obtained with mixtures of three 
salts yielding six of the nutrient ions required for the growth of 
higher green plants. 

Table ii. — Absorption by Lupinus albus seedlings from mixtures of three salts 
having different anions." 

Maximum absorption. 







Solutions. 




N X 10-6 


Percent. 


100 KH 2 P0 4 , 


20 


Ca(N0 3 ) 2 , 


20 MgS0 4 


98.6 


70.4 


80 KH 2 P0 4 . 


40 


Ca(N0 3 ) 2 , 


20 MgS0 4 


1 154 


82.4 


60 KH 2 P0 4 , 


60 


Ca(N0 3 ) 2 , 


20 MgS0 4 


99-4 


71.0 


40 KH 2 P0 4 , 


80 


Ca(N0 3 ) 2 , 


20 MgS0 4 


102. 1 


72.9 


20 KH 2 P0 4 , 


100 


Ca(N0 3 ) 2 , 


20 MgS0 4 


85.9 


60.1 


80 KH 2 P0 4 . 


20 


Ca(N0 3 ) 2 , 


40 MgS0 4 


104-5 


747 


60 KH 2 P0 4 , 


40 


Ca(N0 3 ) 2 , 


40 MgS0 4 


122.3 


87.3 


40 KH 2 P0 4 , 


60 


Ca(N0 3 ) 2 , 


40 MgS0 4 


120.9 


86.3 


20 KH 2 P0 4 , 


80 


Ca(N0 3 ) 2 , 


40 MgS0 4 


99.6 


71. 1 


60 KH 2 P0 4 , 


20 


Ca(N0 3 ) 2 , 


60 MgS0 4 


1 12.7 


80.5 


40 KH 2 P0 4 , 


40 


Ca(N0 3 ) 2 , 


60 MgS0 4 


1 2 3. 1 


879 


20 KH 2 P0 4 , 


60 


Ca(N0 3 ) 2 , 


60 MgS0 4 


1 13-6 


8l. I 


40 KH 2 P0 4 , 


20 


Ca(N0 3 ) 2 , 


80 MgS0 4 


1 12.2 


80.1 


20 KH 2 P0 4 , 


40 


Ca(N0 3 ) 2 , 


80 MgS0 4 


121.6 


86.9 


20 KH 2 P0 4 . 


20 


Ca(N0 3 ) 2 , 


100 MgS0 4 


1 13-0 


80.7 


Average absorption from 3-Sc 


ilt (6-ion) solutions. 


109.7 


78.3 



The original total concentration of each mixture is 140N X io~ 6 . 



From the results above set forth, it appears that with the increase 
of the number of cations, the anion remaining common to them all, 
absorption is markedly increased, reaching in some all-nitrate mix- 
tures over 50 percent of the total number of ions offered. 

When the number of anions is increased by the introduction of the 

P0 4 and S0 4 ions, absorption from solutions containing all six ions 
rises to an average of over 75 percent and in favorable cases reaches 
over 85 percent of the total number of ions present in the solution. 

It appears that when six ions are present the proportions in which 
they occur may exert an important influence. The best results are 
seen when no single ion greatly predominates over the rest. How- 
ever, within these limits a wide range of variation seems to accom- 



106 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



pany almost equal efficiency. There seems to be little evidence to 
support the supposition that any very sharply marked balance must 
be observed. While this seems to be true when the solutions contain 
an increased number of ions, apparently more definite quantity rela- 
tions have a greater significance when fewer ions are present. 

Seedlings in Solutions Containing Three Salts and Iron. 

As none of the mixtures already noted constitute a complete culture 
solution, experiments were undertaken by Dr. Grace A. Dunn, then 
of the Bureau of Plant Industry, working under the direction of the 
writer, designed to shed light on this feature of our problem. 

The details of this work cannot be presented here, but the general 
result was clear in all cases. The presence of any of the iron salts 
commonly used in culture solutions did not in any marked way modify 
the rates of absorption previously found in the 3-salt solutions. It 
seems to be clear, therefore, that the use of iron to the seedling de- 
veloping in darkness is not closely connected with the processes or 
structures decisive for absorption. 

Conclusions. 

The following conclusions may be drawn from the work outlined: 

1. Pure water represents a partial ionic vacuum to roots of 
plants and tends to establish an equilibrium with the cell contents by 
the withdrawal of ions from the plant. This leads in some plants 
and animals to deep seated changes and to consequent injury. 

2. This injurious action is not fully overcome by any one pair of 
ions (salt) tested, but is very largely overcome by salts yielding 
tin- Ca ion, to a very much less degree by those yielding the Mg'ion, 

and but very sligthly or not at all by those carrying the K or Na ions. 

3. The Ca salts most abundantly absorbed are CaCU, CaCO : >, 
and Ca(N0 3 ) 2 . CaS0 4 also is absorbed in an approximately like 
degree by plants that are at home on sandy and acid lands, such as 
aWke clover, whin- lupine, and peanut. For hearty feeders that re- 
quire rich soil and a higher lime content, the absorption from CaSO, 
solutions i> much Less that! from solutions of the other Ca salts 

named. This difference ia probably to be attributed to the influence 

of the anion. The way in which this influence is exerted is reserved 
for fuller disCUSison elsewhere. 

4. The absorption of electrolytes is increased by the increase in 
the number of kind 1 - of nutrienl ions present in the solution. When 
accompanied by Ca ions, K ions, neglected when offered in simple 



TRUE — THE FUNCTION OF CALCIUM. 



107 



solutions, are absorbed. The Ca ions establish conditions that secure 

+ 

the absorption of K ions, or make them " physiologically available " 

and it seems that a similar, but less striking, action by K ions in se- 

+ + 

curing absorption of Ca ions exists. This type of effect is sometimes 
regarded as due to antagonistic action of ions. It seems to the writer 
to be due to the opposite type of action in which one ion helps another 
(synergism) and the increased efficiency coming from united action 
is greater than could be gained by the mere removal by one ion of an 
inhibitory action by another. 6 This is discussed more fully elsewhere. 

5. As the variety of ions present in the solution is increased the 
importance of rather sharply marked proportional relations becomes 
ditsinctly less than in the simpler solutions. Essentially like absorp- 
tion is found to prevail over a rather wide range of proportions pro- 
vided no one ion greatly predominates over the rest or is present in 
too small quantity. The balance in the constituents of the soil solu- 
tion seems not to be a delicate- one for seedlings of plants studied. 

6. Probably the •most striking single chemical condition of the 

solution is the presence of a certain minimal quantity of Ca ions. In 
Lupinus albas seedlings this seems to 1 be a preliminary to the normal 
absorption of ions. Herein is to be seen one of the most important 
functions of calcium in plant nutrition. This seems to be the heart 
of the lime problem in agriculture. A certain minimal quantity of 
Ca ions seems to be necessary to secure the normal absorption of the 
other required ions present in the soil solution. Thru this relation, 
Ca ions make " physiologically available " the other nutrient materials 
contained in the soil solution. 

In the special relation of the S0 4 ion to absorption by seedlings of 
the different physiological types of higher plants, we seem to see a 
basis from which to approach a number of problems connected with 
the practical use of lime, limestone, and gypsum. 

7. The basis for an understanding of the special service performed 

by the Ca ion is doubtless to be sought in the physiology of the cell. 
Lime and limestone doubtless perform highly important work in the 
soil, but their chief utility does not seem to be there. They, with 

gypsum, furnish Ca ions which play as important a part in plant 

nutrition in its strictest sense as K or P0 4 ions. 

6 True, R. H. Antagonism and balanced solutions. In Science, n. s., 41 : 653- 
656. 1915. 



[08 JOURNAL OF THE AMERICAN "SOCIETY OF AGRONOMY. 



NEED FOR LIME AS INDICATED BY RELATIVE TOXICITY OF 
ACID SOIL CONDITIONS TO DIFFERENT CROPS. 1 

Burt L. Hartwell. 2 

The main purpose of this paper is to emphasize that the kind of 
plant to be grown determines, more than any other factor, the amount 
of lime to apply to the soil ; in other words, it is concerning the lime 
requirement for an acre of a given crop plant that agronomists are 
called upon to advise. The term " lime requirement " is understood 
to refer to the amount of calcium carbonate, or material with equiva- 
lent alkalinity, required to counteract other than nutrient effects re- 
sulting from soil acidity, which may be detrimental to crop growth. 

It is not to improve mechanical condition, to influence soil flora or 
fauna, nor to supply, directly or indirectly, strictly plant food ingre- 
dients that attention is given to so-called lime requirements. Only 
when the conditions resulting from these other factors are optimum 
can the relative lime requirements of different crops be determined 
by growing them upon an acid soil. Considerable confusion has 
arisen because mechanical or nutrient effects have not been eliminated 
when such comparisons have been made. It is the alkaline or neu- 
tralizing effect on the plant itself, or on the nutrient medium in which 
it grows, that it is desired to measure. 

The interesting questions relating to just how the alkaline ma- 
terials exert their effects, and to what extent calcium may be re- 
placed by other alkaline elements, are largely avoided in this paper 
in order to observe more clearly the practical considerations con- 
nected with the lime requirements of crops. 

Unless one has observed the comparative effect of lime on crops 
which are extremely different, the importance of this consideration 
is liable to receive less emphasis than it should. As examples of 
pairs of CTOpfl which are similar in many respects, yet very different 
in their lime requirements, mention may be made of watermelon and 

muskmelon, blackberries and raspberries, apple and quince, turnip 

l Contribution 274 from the Agricultural Kxperiment Station of the Rhode 

[•land State College. Presented at the thirteenth annual meeting of the 

\ffierican Society <>f Agronomy, Springfield, M;i^„ October io, 1020. 

Director and agronomist, Rhode Island Agricultural Experiment Station. 



HARTWELL TOXICITY OF ACID SOIL? 



109 



and beet, beans and alfalfa, redtop and timothy, rye and barley. 
Under acid-soil conditions where no lime would be required for the 
first-mentioned of each pair, the requirement for the other may be 
large. Obviously, it serves no useful purpose, therefore, to make a 
statement of the lime requirement of a soil rather than of a crop. It 
seems hardly necessary to state that the measure of the acidity of the 
soil by any method which may be adopted is useful, but it must be 
considered in connection with the crop to be grown before intelligent 
suggestions for liming can be given. 

Furthermore, the evidence is against the idea that diverse crops 
are affected differently by the acidity itself. For example, barley and 
rye are affected alike by a given amount of acid and yet they are in- 
fluenced very differently by the same acid-soil conditions. 

These facts should guard against over confidence in the value of a 
determination of soil acidity by any method. As an indication of a 
set of conditions, the determination is of value, but measurements 
should be made of those soil factors which are connected directly 
with the causes of the wide range in the lime requirements of crops. 

That kind of plant whose growth is inhibited by acid-soil condi- 
tions may be suffering from a deficiency of one thing, such as cal- 
cium bicarbonate ; from a toxic amount of another, such as aluminum; 
or from both. 3 It is scarcely reasonable to expect that an acidity de- 
termination can be correlated closely with such causal factors. 

Excessive applications of acid phosphate to soils well supplied with 
available phosphorus, and yet so acid that certain crops could make 
no growth previously, have so changed the conditions that normal 
growth resulted. The acidity, however, had been much increased, at 
least temporarily, by the acid phosphate. 

Greater attention needs to be given to the relations between the 
nature of the metabolism resulting in the proximate constituents of 
a given crop and the absorption, by the latter, of materials from the 
soil. Altho determinations of certain of these materials are legion, 
comparatively little attention has been given to a consideration of the 
entire amount absorbed per acre. The acre basis is emphasized be- 
cause there is such a wide difference in the average yields of different 
kinds of crops in any locality that the percentage relations are quite 
deceiving. It needs to be kept in mind that we have to deal with the 
lime requirement of a crop per acre, and not per hundred or per ton. 

3 There is an important distinction which should be appreciated between the 
toxicity of aluminum itself, and of the acidity resulting from the hydrolysis of 
its salts. Those who recognized the latter did not thereby discover a reason 
for the great range in the lime requirements of different crops. 



110 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

Concerning many of the ordinary ash analyses it is well under- 
stood that a large part of the chlorin and sulfur, as well as all of the 
nitrogen, disappeared during the incineration ; and yet in nonlegumes 
these ingredients all came from the soil solution, and preferably 
enter the plant in combination as acidic elements. It is of the utmost 
importance to know the relation between the total equivalent of acid 
and of alkaline radicals ; that is, to have a statement of the net alka- 
linity or acidity, as the case may be, of the materials absorbed from 
an acre by our average crops. 

In view of the fact that these materials come from the most active 
part of the soil, a profound difference is, under critical conditions, 
brought about in that particular part by the removal of one instead 
of another of two crops, having, for example, a net difference in the 
reaction of the absorbed materials equivalent to a thousand pounds 
of calcium carbonate. It is not surprising that two such crops should 
have different lime requirements, whether because of their specific 
needs or because of an effect on the soil solution by which the toxicity 
ot certain soil ingredients is inhibited or enhanced, as the case may be. 

Inasmuch as different crops do alter the soil in such, a way that the 
lime requirement of a given crop grown subsequently is distinctly 
modified, one would hesitate to grow, successively, two crops with 
high lime requirement, without positive assurance that the liming was 
sufficient to satisfy the needs of both. On acid soils this effect of 
different crops on a following crop may be very marked, and the 
succession of crops in a rotation under such a condition is an ex- 
tremely important matter regardless of the supply of nutrients. 

Frequently it is inadvisable to satisfy fully the lime requirements 
of a crop because of the development of undesirable associates, for 
example, weeds in a lawn. By selecting a lawn grass which is not 
e to acid-soil conditions, a host of weeds may be warded 
off by withholding lime, an end which is fully justified even tho the 
grass itself does not make the most rapid growth. 

A digression seems warranted here from a consideration of unde- 
sirable conditions accompanying a high degree of soil acidity to 

those which frequently arise when the soil has been neutralized by 
liming. Too many agronomists are stating that soil should be made 
" neutral or slightly alkaline." Doubtless they have in mind the pro- 
ductivity <>i C&lcareoua soils and the nontoxicity of calcium carbonate. 

It is no nrondef thai Dame Nature balks on occasions when mere 
man attempt! to transform a naturally acid soil into a calcareous one. 
Nor is it lOUnd reasoning to overlook the potent changes which take 



HARTWELL — TOXICITY OF ACID SOILS. Ill 

place in the chemistry of the soil in passing from an acid to an alka- 
line reaction. A vision is needed of a test tube containing a solution 
of calcium, iron, and phosphorus and what happens when the neutral 
point is reached by the addition of an alkali. 

Observations of chlorosis, or abnormal green, as well as of growth 
inhibition of crops with low lime requirement, resulting from over 
liming with any form of lime, are sufficiently numerous to suggest 
that as soon as a campaign for the use of lime has become successful 
in any quarter, a second campaign against the over use of lime in that 
same quarter should be launched at once. Otherwise, the same old 
lime " saws " will be found to have as sharp teeth as formerly. 

It is hoped that our commercial lime interests will give heed, for 
we are all too much impressed with the value of liming to enjoy the 
contemplation of anything but the continued economic success of the 
operation from the farmer's standpoint. Only on such a basis can 
the lime industry itself enjoy permanent prosperity. Temporary 
profits which lead to later paralysis must be avoided. 

It will take more than the combined influence of agronomists to 
provide for adequate chemical and physiological study of the intri- 
cate relations of the soil and crop. Business interests must be awak- 
ened to the necessity of retaining in research those with the ability to 
work for the earliest possible solution of practical difficulties. 

If the usual practice of liming only once in every few years shall 
continue, the weather conditions of a single year will fortunately 
have less influence than they do on annual operations. Greater suc- 
cess may be attained therefore in determining lime requirements 
than has rewarded the chemist in his search for methods of deter- 
mining for the farmer the nitrogen, phosphorus, and potassium re- 
quirements for a coming season. Here again the agronomist has fre- 
quently been guilty of fixing attention on the needs of the soil rather 
than on the needs of the individual crop, and has used methods for 
determining phosphorus activity, for example, without regard to 
such facts as that carrots can secure their entire needs for phos- 
phorus under conditions where turnips can scarcely get a start. 

Doubtless we should know the acidity of a soil as measured by the 
concentration of the hydrogen ions and by the concentration of sim- 
ilar factors; the amount of calcium bicarbonate which is generated; 
the amount of active aluminum, not merely the acidity resulting from 
the hydrolysis of its salts ; and much other information about the soil. 
It should never be overlooked, however, that such information must 
be correlated with the response of the individual crop. A PH of 5, 



112 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



an acidity in terms of calcium carbonate per acre equal to 4,000 
pounds by the Veitch method, 5,000 pounds by the Jones method, or 
1 .oco pounds by the Hopkins method, an activity of aluminum rep- 
resented by as high as 0.005 percent, or one of calcium bicarbonate 
by as low as 0.001 percent, must each or all be interpretable in terms 
of the amount of lime required by an acre of beets, for example, if 
they are to be of immediate service to practical agriculture. 

Who is prepared to make these interpretations? Evidently the 
Association of Official Agricultural Chemists has learned conserva- 
tism from experience, for in its latest revision of methods it ventures 
to outline for service in this connection, tentatively, only a qualitative 
test for soil reaction by the use of litmus paper. 

A working plan would be : ( 1 ) Divide those crops which need lime 
into grades 1, 2, and 3, representing low, medium, and high lime re- 
quirements as determined by actual field tests with the crops. (2) 
State specifically for each determination or method believed to be 
useful in connection with the study of the soil, the ranges which are 
supposed to indicate low, medium, and high requirements. (3) 
Designate a small, medium, and large application of lime. 

Such directions as the following might then be useful: A low lime- 
requirement crop to be grown on soil whose chemical reactions indi- 
cate low requirement would need no lime ; if the soil indicates medium 
requirement, the small application of lime would suffice; if the soil 
indicates high requirements, the medium application of lime would 
be enough. For a medium lime-requirement crop the application of 
lime should be small, medium, or large, respectively, depending di- 
rectly upon whether the chemical tests of the soil indicate low, 
medium, or high requirements. For high lime-requirement crops 
the medium Quantity of lime should be added, even when the chem- 
ical tests of the soil indicate a low requirement ; the large quantity 
when the tests of the soil indicate medium requirements; and when 
the t< ts of tin- -oil as well as the kind of crop indicate high require- 
ment, a quantity of lime even in exeess of the standard adopted as a 
large amount may prove profitable. 

\ tentative classification of crops which may need liming has been 
d ade alread) into three grades. Furthermore, it has been suggested 
f t outhern New Kngland that the small, medium, and large appli- 
cation- !>«• equivalent respectively to about 1 ,000, 2,000, and 3,000 
pounds p< r acre of calcium carbonate in finely ground limestone. If, 
in addition, the soil chemists in case of all promising tests will agree 
Upon the range of each of three magnitudes, indicating respectively 
H edittm, and Mgh requirement!, distinct progress has been made. 



CONNER — INJURIOUS INORGANIC COMPOUNDS. 



113 



LIMING IN ITS RELATION TO INJURIOUS INORGANIC 
COMPOUNDS IN THE SOIL. 1 

S. D. Conner. 2 

Lime in its various forms is known to affect soils in a great many 
ways, both chemical and physical. This paper is confined to a dis- 
cussion of the action of lime, both calcium and magnesian, in various 
forms in decreasing the injurious action of inorganic compounds 
which may be in the soil. There are three ways in which lime is 
known to lessen the harmful action of injurious compounds. 

It will neutralize acids in the soil and in this way decrease the 
hydrogen ion concentration. 

It will precipitate many soluble injurious salts. 

It in some cases exerts a so-called and not very well understood 
antagonistic action towards soluble injurious compounds which may 
or may not remain soluble. 

The Reduction of Acidity. 
Several forms of lime reduce acidity more or less. Together with 
the corresponding magnesium compounds, calcium oxid, calcium 
hydroxid, calcium carbonate, calcium silicate, and, to a slight extent, 
calcium phosphate exert such an action. This reduction of acidity 
is beneficial to most agricultural crops. It is now rather widely 
known, however, that it is possible to use too much lime for maxi- 
mum results. There is a certain optimum range of H-ion concentra- 
tion for the soil solution at which crops do best. This varies with 
different crops and in many instances is slightly on the acid side of 
neutrality. 

The Precipitation of Soluble Salts. 

Liming is the most common and cheapest method of precipitating 
soluble injurious compounds in the soil. The soluble injurious inor- 
ganic salts that are found in acid soils are the ones which are pre- 
cipitated by lime. Among such salts may be mentioned aluminum, 
iron, manganese, zinc, and boron. Of all these, aluminum is by far 

1 Contribution from the Purdue University Agricultural Experiment Station. 
LaFayette, Ind. Presented at the thirteenth annual meeting of the American 
Society of Agronomy, Springfield, Mass., October 19, 1920. 

2 Soil chemist, Purdue University Agricultural Experiment Station. 



114 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



the most prevalent. It exists in greater or less quantities in all acid 
soils, depending upon the degree of acidity and the physical character 
of the soil. Soluble salts of aluminum have been known for some 
time to be present in acid soils and to be injurious to plants. Abbott, 
Conner, and Smalley (i) 3 in 191 3 reported experiments upon an 
unproductive acid soil which contained relatively large amounts of 
soluble aluminum salts. It was shown that the aluminum salts were 
the principal toxic agents. Liming precipitated the aluminum and 
rendered the soil more productive. Ruprecht (16) in 191 5 reported 
the presence of soluble salts of aluminum and iron in acid soil at the 
Massachusetts station. Kratzman (11) in 1914 reported that alumi- 
num salts exerted a general poisoning effect upon some plants. 
Miyake's (15) results in 1916 indicated, and Hartwell and Pember's 

(9) in 1 91 8 quite definitely proved that to a certain extent on some 
crops the aluminum ion was toxic rather than the H ion which ac- 
companies it. Just recently Mirasol (14), working at the University 
of Illinois, has obtained results which also indicate that aluminum 
salts are always present in acid soils and are probably the dominant 
factor in affecting plant growth in such soils. 

Iron is seldom found in excessive amounts in soluble form in soils. 
The only forms of iron in the soil known to be injurious to plants are 
the ferrous salts. Ferrous iron salts are only found in poorly aerated 
acid soils. Altho liming would correct soil acidity, it would not 
render a waterlogged soil productive to ordinary crops. Hoffer and 
Carr in unpublished results obtained at the Indiana station working 
in cooperation with the Bureau of Plant Industry have found that 
aluminum and ferrous iron salts exert a distinctly injurious effect 
when introduced into a growing corn stalk. This poisoning does not 
occur with acids of the same strength. They found a similar type 
of injury in corn growing in acid soils. 

Manganese is much more soluble in an acid soil than in a neutral 
one. Skinner and Reid (18) reported experiments in 1916 showing 
that the toxicity of manganese is largely prevented by liming. In 
soils containing excessively large amounts of manganese, however, 
the presence of plenty of lime does not prevent manganese injury 

(10) . Manganese as well as ferrous iron is increased in solubility 
when acid toil* are waterlogged ( 3) , and would no doubt tend to 
exert a harmful influence in the absence of drainage and liming. 
Punches*' (7) L&tesi work shows that soluble manganese salts are 

• o harmful in certain Alabama 901 1 8 as they were at first re- 
porter! to be. 

•Reference l»y number is to 41 Literature cited," p. 123. 



CONNER — INJURIOUS INORGANIC COMPOUNDS. 115 

Sometimes less common inorganic compounds are introduced in 
soils in harmful amounts. In the neighborhood of smelters, sulfuric 
acid, zinc, or arsenic quite often partially or entirely destroy vege- 
tation. Such injury can be to a very great extent prevented by heavy 
liming. Experiments have shown that zinc is not soluble in limed 
soils and not nearly so injurious (4). 

Boron has been added to soil in injurious quantities in some potash 
salts and possibly in some of the nitrates used for fertilizers. The 
use of or the presence of enough lime to render the soil neutral will 
allow the borax to form insoluble combinations in the soil and de- 
crease the damage. This would explain why borax injury was greater 
on acid than on neutral soils (5). 

Antagonistic Action of Calcium. 

Under certain conditions magnesium compounds may exist in soils 
in harmful quantities. Calcium compounds are known to exert a 
more or less antagonistic action and will under some conditions of 
soils and crops neutralize the effect of magnesium poisoning. 

On an acid black loamy sand in a pot test at the Indiana station, 
clover and wheat failed entirely with an application of 4 tons of 
calcium sulfate per 2,000,000 pounds of soil, likewise with a 12-ton 
application of magnesite. Red beets produced no crop with 4 tons of 
calcium sulfate and only 0.5 gram per pot with 12 tons magnesite, 
but in a pot with a combination of 12 tons magnesite plus 4 tons 
calcium sulfate 109 grams of beets were grown, while a 4-ton appli- 
cation of hydrated lime grew only 66 grams of beets. The combina- 
tion of magnesite and calcium sulfate failed to produce any crop of 
corn, buckwheat, or oats. Lime sulfate is often used to lessen the 
injury of sodium carbonate (black alkali). LeClerc and Breazeale 
(12) have recently shown that lime either in the form of oxid or 
sulfate will lessen the toxic action of excessive amounts of sodium 
salts on wheat seedlings. 

Experimental Evidence. 

In view of the fact that, quite large quantities of soluble aluminum 
salts had been found in Indiana acid soils and that the aluminum 
salts had been shown to be toxic ( 1 ) , water culture tests were started 
for the purpose of throwing more light upon the question of whether 
the aluminum ion or the H ion was the toxic agent. The details of 
the complete investigation which was conducted by Mr. O. H. Sears 
and myself will be published in a separate article. Barley and rye 



Il6 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



seedlings were grown in 2,100-c.c. wide-mouth glass bottles. Shive's 
(17) 3-salt stock solutions containing the following salts per 2 liters 
were prepared : 

KHJ?0 4 22.304 grams. 

MgS0 4 6.720 grams. 

Ca(NO,) a 24.270 grams. 

The nutrient solution contained 20 c.c. of each stock solution per 1,000 
c.c. of aerated distilled water, making a concentration of approximately 
0.2 atmosphere osmotic pressure. Two c.c. of dilute ferric citrate 
were added to each bottle, and 60 c.c. lime water was also added as 
the nutrient was slightly acid. Four strengths of sulfuric acid and 
four strengths of aluminum sulfate were used. Series were carried 
in duplicate and continued four weeks. The total plants were dried 
and weighed. 



Table i. — Relative weights of barley and rye grown in water cultures of 
Skive's nutrient solution. 



No. 


Treatment. 


ct2 


PH. 


Relative 
Barley. 


weights. | 
Rye. 


I 


H0SO4 


6.0 


3-6 


30.5 


43 


2 


HeSO, 


3-7 


4-3 


50.1 


31 


3 


H 2 SO< 


2.7 


5-o 


53-8 


72 


4 


HsSO* 


2.2 


5-7 


93-9 


103 


5 


A1 2 (S0 4 )3 


10. 


3-9 


33-8 


43 


6 


A1j(SO0i 


6.0 


4-3 


63-7 


71 


7 


Al 2 (S04b 


4.2 


5-0 


93-4 


75 


8 


A1 2 (S(>4)3 


2.9 


5-7 


96.1 


84 




Check 




6.3 


100.0 


100 



Hydrogen-ion determinations were made by the colorimetric method. 
Solutions were changed daily so there would be no change in H-ion 
concentration. Weights given arc relative to 100 for the checks. 
The results of this test and of several preliminary tests run at pre- 
vious dates indicated that the toxicity of aluminum sulfate was due 
entirely to the H ion and not to the aluminum. However, in the cul- 
tttrei containing aluminum sulfate, there was quite a distinct pre- 
1 pitatr, indicating that the aluminum had been thrown out of solu- 
tion probably by phosphorus. The Shive's ( 17) nutrient used con- 
26 time- as much phosphorus as I lartwell and Pember's (9) 
nutrient. The following amounts of different elements were con- 
tained in the two nutrient solution- used. 



CONNER INJURIOUS INORGANIC COMPOUNDS. II7 

Table 2. — Grams of various elements per 1,000 c.c. of nutrient solution. 

bhive's. Hartwell and Pember's. 



P 0.055 0.002 

N 042 .070 

K 067 .030 

Ca 060 .053 

Mg 013 , .020 

S 018 .026 



To throw more light upon this point a series of water cultures were 
run with the nutrient prepared according to Hartwell and Pember. 
The results are shown in Table 3. 



Table 3. — Relative weights of barley and rye grown in water cultures of 
Hartwell and Pember's nutrient solution. 



No. 


Treatment. 


C.c. 2. 

5 


PH. 


Relative 
Barley. 


weights. 
Rye. 


I ' 


H2SO4 


2.00 


3-9 


73 


65 


2 


H2SO4 


1. 00 


4.2 


93 


95 


3 


H2SO4 


•So 


5-0 


90 


90 


4 


H2SO4 


•25 


5-7 


101 


95 


5 


Al2(S0 4 )3 


5.00 


3-9 


47 


55 


6 


A1 2 (S0 4 )3 


1.30 


4.2 


68 


65 


7 


A1 2 (S0 4 ) 3 


.75 


5-0 


91 


80 


8 


A1 2 (S0 4 )3 


.50 


5-7 


121 


90 


9 


Check 




6.3 


100 


100 



The results from the test with Hartwell and Pember's nutrient which 
is very low in phosphorus and which did not precipitate the aluminum 
indicate that not only is the H ion toxic but that the aluminum itself 
is toxic especially to barley in the more acid concentrations. A 
comparison of the results from tests with the two nutrient solutions 
indicate that phosphorus is to a certain extent an antidote and will 
decrease the harmful action of aluminum salts. When 2,100 c.c. of 
Hartwell and Pember's nutrient is used and changed daily, the Check 
and weaker acid treatments show no lack of phosphorus. 

POT TESTS. 

In a series of pot tests on an acid black loamy sand soil started in 
February, 1918, several different materials were applied, all at the 
rate of 4 tons per 2,000,000 pounds of soil. All pots had a uniform 
treatment of 31 lbs. N, 160 lbs. P 2 5 , and 108 lbs. K 2 per acre, in 
the form of diammonium phosphate and dipotassium phosphate. 
Red beets were harvested May, 1918; popcorn in September, 1918; 
buckwheat, March, 1919; and oats, October 1, 1919. The results are 
given in Table 4. 



Il8 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 4. — Grains of various crops per pot produced in pots of acid black sand, 
with acidity at end of test. 

















Acidity. 


Pot No. 


Treatment. 


Beets. 


Corn. 


Buckwheat. 


Oats. 


PH. 


Hop- 












Jones. 
















kins. 


3 


None . . . . ! 





O 


a O 


a .05 


4.2 


2,500 


12,50,0 


18 


H3PO4 


•5 


5-0 


°-5 


a -5o 


4.1 


3.080 


13.500 


19 


CaH 4 (P04)2 


160.0 


48.0 


a -5 


a .20 


4.2- 


1,800 


12,500 


20 


Acid phosphate 


•5 





a .s 


a -50 


4-1 


2,700 


12,500 


21 


Ca 3 (PC>4)2 


271.0 


16.0 


°.6 • 


a .6o 


4.4 


1,000 


9.50O 


22 


Ca(OH) 2 ; . 


240.0 


•5 


29-5 


3-8o 


6.0 


160 


6,500 


23 


Ca 2 SiC>4 


285.0 


44-0 


14-5 


9.00 


6.0 


340 


7,500 


24 


H 2 Si0 3 


5-0 





a .i 


a .20 


4.2 


2,840 


12,000 



" Yields probably depressed by zinc salts dissolved from galvanized pots. 



Figure 2 shows the relative growth of red beets, popcorn, and 
Silverhull buckwheat with various tratments in acid black sand soil. 

The results obtained in this series of pot tests can be explained on 
the basis of aluminum toxicity. This is the same soil reported in 
Purdue Univ. Agr. Expt. Sta. Bui. No. 170, and in which large 
amounts of soluble aluminum salts were found. The determinations 
of acidity and of the H-ion concentration of soil from each pot shows 
that the crops were not in proportion to the H ions or acidity by other 
methods. The basic fertilizer furnished ample supplies of plant food. 
The obvious explanation lies in the fact that aluminum salts are toxic 
and that aluminum phosphates and aluminum silicates are much more 
insoluble than aluminum hydroxid. In pots 19 and 21 the phosphates 
had reduced the aluminum salts but had left a fairly high degree of 
acidity, yet the yields of both beets and corn were good. When corn 
was grown in pot 18 with the highest acidity of all, a 4-ton applica- 
tion of 85 percent liquid phosphoric acid produced more corn than 
pot 22 with the least acidity. While excessive acidity is injurious to 
corn, it would seem that in certain ranges the aluminum ion is even 
more toxic than the H ion. The reason buckwheat and oats failed to 
make growth with the phosphates is probably due to the toxic action 
of zinc which was dissolved in the soil from the galvanized pots (4). 
It is interesting to note that with the first, second, and fourth crops 
grown, calcium silicate produced greater crops than calcium hydroxid 
with practically the same soil acidity. This is also in accord with the 
theory 01 aluminum toxicity, aluminum silicate as well as aluminum 
phosphate being much less soluble than aluminum hydroxid at the 
•ame H-ion concentration. This might be the reason why calcium 
silicate has sometimes given better results than lime in soil tests by 
(r >. i. 7 )) The reason 4 tons per acre of acid phosphate did 
not produce as good results as 4 tons of monocalcium phosphate is 



a 1 X N ES — IN J URIOUS I NORGA NIC COM POU NDS. 



119 



Rh. 9.1 4.2- 4-.J 4* *-0 6.0 #A 





Fig. 2. Growth of red beets, popcorn, and buckwheat on acid black sand with 
lime, phosphates, and silicates. 



120 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



because there was not so much phosphoric acid applied. In a later 
pot test on this soil a 15-ton per acre application of acid phosphate 
produced good results on corn, while a 5-ton application of calcium 
carbonate failed entirely. 

LABORATORY TESTS. 

To determine the relative solubility of aluminum hydroxid and 
aluminum phosphate at different H-ion concentrations, a series of 
precipitations were made. To 5 c.c. portions of fifth-normal alumi- 
num nitrate were added varying amounts of half-normal sodium hy- 
droxid. The H-ion concentration and the weight of precipitate were 
determined. In a like manner 2 c.c. N/2 KH 2 (P0 4 ) was added to 
5 c.c. N/5 A1(N0 3 ) 3 and precipitated at different H-ion concentra- 
tions and the precipitates weighed. Table 5 gives the results of 
these tests. 

Table 5. — Relative solubility of Al 2 0» and A1P0* at different H-ion 

concentrations. 



PH. 



NaOH. 



ai 2 o 3 . 



NaOH. 



AIPO4 



3-3 

3-5 

3-8 

3- 9 

40 

4- 3 

4- 8 

5- 

5-3 

5- 4 

6.0 

6- 3 

M 

''•5 

6.6 



Cubic centimeters. 



1.20 
1 .40 
1.50 
1.60 



1. 65 
1.70 



I So 



Grams. 



.0009 
.0012 
.0014 
.0014 

.0140 
.0168 



.0166 



Cubic centimeters. 

.0 

•50 
1. 00 
1.20 
1.30 
i-35 
1.40 



i-45 
1.50 



1.60 
1.80 



Grams. 
o 

.0092 
•0356 
•0363 
.0364 
•0344 
•0332 



.0332 
.0326 



•0325 
.0311 



The results shown in Table 5 indicate that it is possible to pre- 
cipitate soluble aluminum salts in a soil with phosphates at P11 3.9 
more completely than A1.,0 :! can be precipitated with lime at Ph 6.0. 
This would explain why corn, which is sensitive to the aluminum 
ion, grew better at Ph 4.2 with 4 tons monocalciutn phosphate than it 
did at I'ii 6.0 with 4 tons hydrated lime. These Al 2 O s solubilities are 
in accord with the results obtained by Blum (2). 

iiii.i) TESTS. 

In 192O a s ( ru . s ,,f geld tests wtft started on a new experiment 
field at Wanatali. Limestone was used at the uniform rate of 4 tons 



CONNER — INJURIOUS INORGANIC COMPOUNDS. 



121 



per acre on a series of plats. Other treatments were given as shown 
in Table 6. Oats, corn, and soybean-millet hay have been harvested. 

Table 6. — Yields of oats, corn, and soybean-millet hay on plats variously 
treated on Wanatah field, 1920. 



Treatment per acre Yield per acre. 



Limestone. 


KC1. 


Acid 
phosphate. 


Rock 
phosphate. 


Calcium 
silicate. 


Oats. 


Hay. 


Corn. 


Pounds. 


Pounds. 


Pounds. 


Pounds. 


Pounds. 


Bushels. 


Pounds. 


Bushels. 


O 











° 


a 34 


a i,o8o 


a i.8 


8,000 














*40 


b i.557 


6 5-4 


8,000 


100 











36 


1,697 


5-6 


8,000 





300 








45 


1,580 


8-5 


8,000 


100 


300 








45 


1,842 


H-5 


8,000 


100 


300 





2,000 


57 


2,529 


19.2 


8,000 


100 


1,000 





O 


62 


3.787 


17.9 


8,000 . . : . . 


100 




2,000 


O 


4i 


1,997 


10.3 



a The untreated yield is an average of three plats. 
* The lime alone is an average yield of eight plats. 



Where 300 pounds acid phosphate, an amount sufficient to furnish 
phosphorus for all plant-food needs of the crops, was applied in addi- 
tion to lime, maximum yields were not obtained; but where 1,000 
pounds of acid phosphate was applied the yield of oats was increased 
17 bushels per acre, corn about 6 bushels per acre, and the soybean- 
millet hay yield was doubled over the normal acid phosphate yield. 
Likewise the i-ton application of calcium silicate gave an increase of 
12 bushels of oats, 7 bushels of corn, and 700 pounds of hay over the 
lime, potash, and phosphate treatment. These results also indicate 
that both the heavy phosphate and the calcium silicate treatments 
had exerted an effect other than furnishing plant food. This effect 
can be explained on the basis of more complete precipitation of 
toxic aluminum salts. 

We have never been able to grow a normal corn crop on this soil 
even with limestone applications up to 14 tons per acre until after a 
lapse of three years. It is quite possible that the aluminum hydroxid 
remains toxic until it is gradually fixed as a single or double silicate 
or phosphate or in a more insoluble hydroxid. At any rate, plenty 
of available phosphate or silicate hastens the improvement in fertility 
and crop-producing power. 

It is a widely observed fact that acid soils almost universally re- 
spond to phosphate fertilizers. It is quite probable that at least a 
part of this response is due to the action of phosphates in reducing 
soluble aluminum salts in acid soils. The Rothamsted results show 



122 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



that barley is a crop that responds to phosphate more than almost 
any other crop. The Rhode Island results as well as the Indiana 
tests show that barley is particularly sensitive to aluminum toxicity. 

In water cultures we have found that young seedlings which had 
been stunned by aluminum salts were more or less permanently in- 
jured and were seemingly unable to recover when placed in normal 
nutrient solutions. In 1847, Sir John Lawes (8) wrote, "Whether 
or not superphosphate of lime owes much of its effect to its chemical 
actions in the soil, it is certainly true that it causes a much enchanced 
development of the underground collective apparatus of the plant, 
especially of lateral and fibrous roots." Many instances have been 
noted where a small amount of acid phosphate applied in the drill has 
produced increases much greater than the amount of phosphorus as 
a plant food would seem to warrant. This effect may well be due 
partly to the protective action of phosphate on the young seedling. 

All the evidence at hand shows conclusively that lime is a powerful 
agent in improving the chemical condition of the soil and in correcting 
the toxic influence of injurious inorganic compounds contained 
therein. It is also evident that lime alone is not always sufficient but 
that phosphorus is generally needed to supplement lime in the im- 
provement of acid soils. 

Summary. 

1. Lime may act on injurious inorganic compounds in the soil in 
three ways: 

(a) It neutralizes soil acidity by decreasing the H-ion concen- 
tration. 

(b) It precipitates most injurious soluble salts which are found in 
acid soils. 

(c) It, to a certain extent, acts in an antagonistic manner towards 
excessive soluble salts which may not be precipitated. 

2. Aluminum, iron, manganese, boron, and zinc in soluble forms 
are harmful but they may be rendered less soluble and less injurious 
by lime. 

3. Much of the harmful acidity of acid soils is due to the presence 
of soluble aluminum salts. 

4. Aluminum toxicity is at least partly due to the aluminum ion. 
Thil action is more pronounced with barley than with rye. 

5. The presence of abundant phosphates in the nutrient prevents 
aluminum injury, by precipitation. 

6. Red beets were grown in an acid soil with the addition of mono- 
calcium and tricalcium phosphate, calcium hydroxid, and dicalcium 
rilicate. 



CONNER INJURIOUS INORGANIC COMPOUNDS. 



123 



7. Popcorn grew with all these materials except calcium hydroxid. 

8. The growth of beets and corn was not in proportion to the 
H-ion concentration or soil acidity. 

9. At Ph 3.9 aluminum is more completely precipitated as a phos- 
phate than it is at Ph 6.0 as a hydroxid. 

10. Aluminum is much more insoluble as a silicate than it is at the 
same acidity as a hydroxid. 

11. In field plats, lime alone did not produce optimum crops on an 
acid black sand. Half a ton of acid phosphate or 1 ton of dicalcium 
silicate per acre produced good crops on limed land. 

12. On sandy and peaty acid soils low in active silica, liming should 
be supplemented by available phosphates to correct aluminum toxicity. 

13. The more active forms of silicates to a certain extent aid in 
precipitating aluminum salts. 

LITERATURE CITED. 

1. Abbott, J. B., Conner. S. D., and Smalley. H. R. Soil acidity, nitrifica- 

tion, and the toxicity of soluble salts of aluminum. Ind. Agr. Expt. Sta. 
Bui. 170. 1913. 

2. Blum, Wm. The determination of aluminum as oxide. In Jour. Amer. 

Chem. Soc, v. 38, no. 7, p. 1282-1297. 1916. 

3. Conner, S. D. Soil acidity as affected by moisture conditions of the soil. 

In Jour. Agr. Research, v. 15, no. 6, p. 321-329. 1918. 

4. . The effect of zinc in soil tests with zinc and galvanized iron pots. 

In Jour. Amer. Soc. Agron., v. 12, no. 2, p. 61-64. 1920. 

5. , and Fergus, E. X. Borax in fertilizers. Ind. Agr. Expt. Sta. Bui. 239. 

1920. 

6. Cowles, A. H. Calcium silicates as fertilizers. In Metallurg. and Chem. 

Eng., v. 17, p. 664, 665. 1917. 

7. Funchess, M. J. Acid soils and the toxicity of manganese. In Soil Sci., 

v. 8, no. 1, p. 69. 1919. 

8. Hall, A. D. Fertilizers and Manures, p. 139 (quotes Sir John Lawes). 

Dutton & Co., New York. 1909. 

9. Hartwell, B. L., and Pember, F. R. The presence of aluminum as a reason 

for the difference in the effect of so-called acid soil on barley and rye. 
In Soil Sci., v. 6, no. 4, P- 259-277. 1918. 

10. Kelley, W. P. The influence of manganese on the growth of pineapples. 

Hawaii Agr. Expt. Sta. Press. Bui. 23. 1909. 

11. Kratzman, E. Action of aluminum salts on plants. In Chem. Ztg., v. 38, 

p. 104c. 1914. 

12. LeClerc, J. A., and Breazeale, J. F. Effect of lime upon the sodium- 

chlorid tolerance of wheat seedlings. In Jour. Agr. Research, v. 18, no. 
7, p. 347-356. 1920. 

13. MacIntire, W. H., and Willis, L. G. Comparison of silicates and car- 

bonates as sources of lime and magnesia for plants. In Jour. Indus, and 
Eng. Chem., v. 6, no. 12, p. 1005-1008. 1914. 

14. Mirasol, J. J. Aluminum as a factor in soil acidity. In Soil Sci.. v. 10, 

no. 3, p. 153-193- 1920. 



124 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



15. Miyake, K. The toxic action of soluble aluminum salts upon the growth 

of the rice plant. In Jour. Biol. Chem., v. 25, no. 1, p. 23-28. 1916. 

16. Ruprecht, R. W. Toxic effect of iron and aluminum salts on clover seed- 

lings. Mass. Agr. Expt. Sta. Bui. 161. 1915. 

17. Shive, J. W. A study of physiological balance in nutrient media. In 

Physiol. Researches, v. 1. no. 7, p. 327-397. 1015. 
iS. Skixxer. J. J., and Reid. F. R. The action of manganese under acid and 
neutral soil conditions. U. S. Dept. Agr. Bui. 441. 1916. 

THE EFFECT OF LIMING ON THE COMPOSITION OF THE 
DRAINAGE WATER OF SOILS. 1 

T. L. Lyon. 2 

Xot many experiments have been conducted in which a study of 
the effect of liming on the composition of the drainage water of soils 
lias been a feature. Applications of potash salts, both muriate and 
sulfate, have more commonly been made and these have usually re- 
• suited in rinding that such applications increase the removal of cal- 
cium and magnesium in the drainage water. As calcium is a cheaper 
soil amendment than potassium it is worth while to know whether 
liming a soil will liberate potassium and also what other phenomena 
may be noted by means of the drainage water as the result of appli- 
cations of lime. This may also give some information as to wlr> 
liming is so often beneficial to soils and may help to clear up the mys- 
tery which seems to surround the condition commonly called "soil 
acidity." As yet. however, the study of drainage water has not 

n pressed Ear enough to throw much light on the "acidity" problem. 
In n viewing the literature on the subject the various papers will 
he lakeii up in chronological order unless there is some special reason 
for doing otherwise. Only those investigations will be reviewed in 
which calcium or magnesium compounds have been applied to the 

oil. Applications of potassium salts will not be included. The term 
liming will he used to mean the application of calcium compounds 
< nly. When applications of magnesium compounds are considered 
• < are IK,; included under liming but are referred to as the specific 

lib tance. This is abo true of applications of dolomite. 

Uvm\ \>\ title in the absence of the author ;it the thirteenth annual meeting 
of the American So ety of Agronomy, Springfield, Mass., October 19, 1020. 
( ontrilwtions from the Department of Soil Technology, Cornell University 
nltural I xperiment Station, Ithaca, N. Y. 

• •r of soil tccliti'iloKy in the College of Agriculture of Cornell 

I'nivcrMty. 



LYON COMPOSITION OF DRAINAGE WATER. 125 

One of the few European experiments with lysimeters in which 
lime was applied to soils was conducted by Tacke, ImmendorfT, and 
Minssen (8), 3 who used moor soil in small containers. Applica- 
tions of lime did not increase the quantity of calcium in the drainage 
water. Only after repeated applications of lime was there any ap- 
parent liberation of potassium by the soil. Moderate applications of 
lime did not have much effect on the quantity of nitrates that ap- 
peared in the drainage water. Larger applications of lime "resulted in 
increased nitrification in the soils poor in calcium but had little influ- 
ence on soils rich in calcium. 

Eckart (2) conducted experiments with lysimeters, each holding 
250 pounds of soil which was sandy but high in calcium. In a series 
of these vessels 100 grams of lime per 100 pounds of dry soil were 
applied in different compounds. Burnt lime, ground coral, and gyp- 
sum were used. Determinations of nitrate nitrogen in the drainage 
water showed that there was no increase of nitrification resulting 
from the use of burnt lime and possibly a slight decrease. Ground 
coral increased nitrification quite markedly while gypsum depressed 
it strongly. In the same experiment gypsum increased the quantity 
of potash in the drainage water at the rate of 198 pounds per acre, 
but burnt lime and ground coral did not cause any significant increase 
in the solubility of the potash. Gypsum also effected an increased 
removal of calcium, but burnt lime and ground coral did not. 

Peck (7) also conducted lysimeter experiments at the Sugar 
Planters' Experiment Station in Hawaii, altho he did not use the 
same containers as did Eckart. Peck's vessels were 8 inches in diam- 
eter and 2 feet in depth. Two soils were used, both of which were 
sandy loams. One, an upland loam, was acid to litmus ; the other 
from lowland, was alkaline to litmus. To one set of vessels contain- 
ing the acid soil lime was applied in the forms of oxid, carbonate, and 
sulfate, a sufficient quantity of each being used to supply calcium oxid 
at the rate of 1 ton to the acre foot. To the alkaline soil calcium 
oxid was applied. The soils were kept free of vegetation. The ves- 
sels were irrigated with distilled water at intervals of two weeks, and 
ten irrigations were given, amounting in all to about 23 vertical 
inches. 

All three forms of lime increased nitrification in the acid soil, but 
with the alkaline soil the only form of calcium applied, the oxid, de- 
pressed nitrification to a very great degree. In the acid soil all three 
forms of lime increased the quantities of calcium and potassium in 

3 Reference is to " Literature cited," p. 130. 



126 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



the drainage water, but in the alkaline soil calcium oxid caused very 
little difference in these constituents. 

Both Eckart and Peck are inclined to attribute the depressing effect 
of burnt lime on nitrification to an undue alkaline reaction of the 
soil caused by the application. The depressing effect was not noted 
in the acid soil used by Peck. 

Broughton (i) treated three soils, a sand, a clay, and a loam, with 
commercial lime in the forms of burnt lime (oxid), ground limestone, 
ground oyster shells, phosphate of lime, and gypsum. He also used a 
pure calcium oxid. The soils were placed in large stoneware jars 
glazed inside and out and having an outlet on the side near the bottom. 
A set of each was placed in the greenhouse and another set outside, 
all being allowed to stand for one year. The various forms of lime 
were applied in equal quantites of calcium at the rate of 4,000 pounds 
of CaO per acre and mixed with the upper 6 inches of soil. Water 
was poured on the surface of the soil in the greenhouse pots in 
amounts and at intervals corresponding to the average amount and 
distribution of rainfall for a series of years. The outside pots re- 
ceived the natural rainfall. The drainage was collected for one year, 
measured, and calcium determined. 

The clay soil lost much less calcium in the drainage water than did 
either the sand or loam, between which soils there was little differ- 
ence. As there was no untreated soil it is not apparent that the appli- 
cation of lime increased the removal of calcium. 

Of the various forms of lime, gypsum caused by far the greatest 
loss of calcium. There was appreciably more calcium removed from 
the -oils to which limestone was applied than from those to which 
burnt lime was added and this was true with each of the three soils. 
Rock phosphate treated soils gave less calcium in the teachings than 
did any of the form- of lime used in the experiment. 

MacTntirc, Willis and Molding (5) analyzed the drainage water 
from a mellow sandy loam soil contained in a number of galvanized 
iron cylinders with drainage pipe at the bottom. About half of these 
cylinders held 1 fool of surface soil and in the other half a I-foot 
layer of Milfoil wa^ placed beneath the surface layer. Duplicate ves- 
n ere treated w ith calcium oxid and carbonate in chemically 
equivalent quantities of calcium and with magnesium carbonate, the 
treatments in each case being in three graduated quantities consisting 
of K. v. and 100 ions of CaO per acre or chemical equivalent quanti- 
ties of the other substances. 



LYOX COMPOSITION OF DRAINAGE WATER. 



127 



Drainage water was collected during a period of two years and 
the sulfur content determined. It was found in every case in which 
the subsoil was present that the quantity of sulfur in the drainage 
water was much less than where there was no subsoil, except in the 
second year where MgO or MgC0 3 were used. 

The effect of the 32-ton and 100-ton applications of CaO was to cut 
down the quantities of sulfur in the drainage water below that pres- 
ent in the leachings from the 8-ton treatment. The correspondingly 
large applications of MgO did not have this effect nor did the addi- 
tion of CaCO s or MgCO s . In fact, the application of magnesium 
compounds always increased the quantity of sulfur as compared with 
applications of calcium compounds. 

Lyon and Bizzell (3) conducted lysimeter experiments with two 
soils, one a heavy clay loam and the other a silt loam. The lysimeters 
were 4 feet deep. The application of burnt lime at the rate of 3,000 
pounds per acre did not increase the quantity of calcium in the drain- 
age water of the former soil but it did in that of the latter. The soil 
from which there was no increased removal of lime by leaching con- 
tained more than twice as much calcium as the other. It contained a 
larger proportion of clay, which presumably gave it greater ab- 
sorptive capacity. 

In both soils magnesium was removed in greater quantity when the 
soil was limed. Potassium on the other hand was conserved in both 
soils by liming. In the case of the one soil the drainage water of 
which was analyzed for sodium that element was affected similarly 
to potassium by the application of lime. 

In the finer textured soil, which was the one containing the larger- 
quantity of calcium, the addition of lime did not increase the nitrate 
nitrogen in the drainage water but in the other soil it did. The effect 
on sulfur was directly contrary to the effect on nitrogen in that the 
soil in which nitrogen removal was increased by liming lost less sulfur 
and vice versa. It may be remarked that the soil in which liming did 
not increase the removal of sulfur had less apparent absorptive 
capacity than the other and that the failure of sulfur to be liberated 
was apparently not caused by absorption by the lower soil. 

Maclntire (6) points out that there may be direct and substitutive 
absorption of lime. In the former case the Ca may be taken up by 
acid silicates or silicic acid, while in the latter the substitution of Ca 
for the alkali or alkali earth elements may take place and may or 
may not result in the loss of the liberated bases. He obtained little 
leaching of K or Xa. The different forms of lime. CaO, Ca(OH) 2 , 
and CaCOo, showed little difference in substitutive effect. 



128 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The leachings of calcium were as large from the minimum or 
8-ton CaCO r> treatment as from the maximum or 100-ton treatment. 
In the case of treatments of equivalent quantities of CaO and CaCO s 
the former caused much larger losses of Ca in the leachings, espe- 
cially with large treatments. 

The above results were all obtained from i-foot layers of top soil. 
In tanks which contained subsoil there was less loss of Ca in the 
leachings than from those containing only top soil. 

Some unpublished data of Maclntire's indicate that treatments of 
MgO to top soil in quantities of 2,000 and 3,750 pounds per acre and 
of 8 to 100 tons resulted in conserving the loss of Ca in the leach- 
ings. The quantities of Mg in the leachings were, however, much 
greater than where lime was applied. 

McHargue (4) analyzed the water of streams in Kentucky and 
elsewhere draining limestone areas and for purposes of comparison 
made analyses of streams draining other formations, notably sand- 
stone and shale. He found that the former contained larger amounts 
of phosphorus, calcium, and nitrates, while the latter were usually 
richer in potassium and in some instances in magnesium, sodium, 
sulfur, and chlorin. The areas drained by these streams were cov- 
ered by residual soils which are characteristic of the formations, 
those of the limestone areas in Kentucky being rather heavy clays 
while those of the coal measures farther east in that State and in 
western Pennsylvania were sandy. The potassium in the waters 
from the coal measures was more than twice that found in waters 
from the limestone formations, which he attributes to differences in 
the absorptive properties of the soils on the two areas. The lime- 
stone soils he states contained much more potassium in spite of the 
fact that they lost less in the drainage water. 

As the limestone soils are richer in calcium than the others it 
would be natural that they would lose more. It is also probable that 
the limestone soils contain more nitrogen, so that the presence of 
large amounts of calcium can not necessarily be considered to be the 
I'.'iiM- of tin- larger removal of nitrate nitrogen. 

SUMMARY. 

Applications of calcium oxid and carbonate usually increase nitri- 
fication aild removal of nitrogen in drainage water. In some soils 
there is no IUCh result, which in sonic of the experiments reviewed is 
to be accounted for by partial sterilization. In other cases it 



LYON COMPOSITION OF DRAINAGE WATER. 



129 



may be explained by high absorptive properties of certain soils, by 
reason of which lime, in moderate quantities, has comparatively little 
effect on the composition of the soil solution and therefore on nitri- 
fication. 

Gypsum appears to have a depressing effect on nitrification and 
nitrogen removal when applied in the comparatively large quantities 
in which the other forms of lime are usually applied, but there are 
exceptions to this. When used in the quantities that would be pres- 
ent in ordinary applications of acid phosphate there may not be such 
an effect, but lysimeter experiments have not been conducted with 
such quantities. 

The effect of liming on the removal of sulfur in the drainage water 
is difficult to understand. Apparently when conditions are made 
more favorable for nitrification they are not always more favorable 
for sulfofication. In other words, when liming increases nitrification 
it may or may not promote sulfofication. The data do not permit 
any further generalization. There is some indication, however, that 
a subsoil may absorb much of the sulfate formed in the upper soil. 

Excessive applications of calcium oxid may depress the sulfofying 
process but this is not true of equivalent applications of carbonates 
of calcium and magnesium. The influence of the oxid in this case 
may be due to partial sterilization of the soil. It would be interesting 
if figures for nitrogen in drainage water from the same soils were 
available. Magnesium oxid and carbonate are more potent in effect- 
ing removal of sulfur than are the same compounds of calcium. 

Liming with oxid or carbonate has in many cases increased the 
removal of calcium in the drainage and in somewhat fewer instances 
it has not done so. Clay soils with great absorptive capacity either 
did not give off calcium when limed or did so to less degree than did 
more sandy soils. It seems probable that the magnitude of the ab- 
sorptive capacity determines the ability of a soil to prevent the libera- 
tion of calcium when lime is applied. Magnesium appears always to 
be liberated when a soil is limed. Gypsum invariably increases re- 
moval of calcium and probably of magnesium altho there are less data 
for the latter substance. 

Potassium rarely appears in larger quantities when a soil is limed 
with carbonate or oxid. There may be some soils in which potassium 
is thus liberated but this does not appear to be a normal circumstance, 
especially when the drainage passes thru a subsoil. Gypsum, on the 
other hand, more frequently effects a liberation of potassium. 

So far as phosphorus is concerned there is to be found so little in 



130 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

drainage water that nothing has been learned regarding it by means 
of lysimeter experiments. 

LITERATURE CITED. 

1. Broughtox, L. B. How lime is distributed through and lost from soil. Md. 

Agr. Expt. Sta. Bui. 166, p. 285-326. 1912. 

2. Eckart, C. F. Lysimeter experiments. Hawaiian Sugar Planters' Assn. 

Expt. Sta. Bui. 19, p. 1-31. 1006. 

3. Lyon, T. L., and Bizzell. J. A. Lysimeter experiments. Cornell Univ. Agr. 

Expt. Sta. Memoir 12, p. 7-1 13. 1918. Also unpublished data. 

4. McHargue, J. S. The removal of mineral plant food by natural drainage 

waters. Unpublished. 

5. MacIxtire, W. H., Willis, L. G., and Holding, W. A. The divergent 

effects of lime and magnesia upon the conservation of soil sulfur. In 
Soil Sci., V. 4. P- 231-235. 1917. 

6. MacIntire, W. H. The carbonation of burnt lime in soils. In Soil Sci., 

v. 7. p. 325-446. 1919. Also unpublished data. 

7. Peck, S. S. Lysimeter experiments. Hawaiian Sugar Planters' Assn. Expt. 

Sta. Bui. 37. P- 3-38. 191 1. 

8. Tacke, Br., Immendorff, I^., and Minssen, H. Untersuchungen iiber die 

Zusammensetzung der Sickerwasser aus nichtgedungtem und aus gedung- 
tem Moorboden mit besonderer Berticksichtigung der' Stickstoffver- 
bindungen. In Landw. Jahrb., Bd. 27, Erganzungsband IV, S. 349-391. 
1898. 



AGRONOMIC AFFAIRS. 



131 



AGRONOMIC AFFAIRS. 

BACK NUMBERS OF THE JOURNAL. 

The editor has in stock varying numbers of each issue of the 
Journal of the American Society of Agronomy and also copies 
of the Proceedings, four volumes of which were issued prior to the 
establishment of the Journal in 191 3. It is desirable that the storage 
space occupied by these volumes be reduced, and also that the Society 
obtain such funds from them as may be possible. Members who 
have joined in recent years are urged to purchase as many of these 
volumes as they feel they can afford and can use to advantage. Copies 
can be seen in almost any of the experiment station libraries, and 
members can thus decide just which volumes are likely to prove most 
valuable to them. The reduced prices at which back volumes can 
be purchased by members will be quoted on request by the secretary- 
treasurer or the editor. In general, remittance drawn to the Ameri- 
can Society of Agronomy should accompany the order. As some of 
the volumes are in stock in limited numbers only, agronomists will 
do well to make sure that college and station libraries have com- 
plete sets. 

More copies are on hand of many individual issues of the Journal 
than can be used in making up complete volumes. Members who 
keep a file of the publication can usually obtain missing numbers on 
request addressed to the editor. So far as these can be supplied 
without breaking volumes, they will be sent free. On the other hand, 
those who do not wish to maintain a file of the Journal will confer a 
favor on the Society by returning to the editor their copies of Volume 
5, Xo. 1, and Volume 8, No. 4, the stock of which is particularly 
low. Complete copies of Volume 8 or any of the individual numbers 
of that volume can be used to advantage. 

MEMBERSHIP CHANGES. 

The membership reported in the February Journal was 582. 
Since that report, 22 new members have been added and 8 members 
have been reinstated, while 3 have resigned. These changes have 
resulted in a net gain of 27, making the present membership 609. 
This is still far short of what it should be, and members everywhere 



1^2 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

are urged to use their best efforts to bring the Society to the attention 
of agronomic workers who do not now belong to it. 

NOTES AND NEWS. 

Elmer D. Ball, professor of zoology at Iowa State College and as- 
sistant secretary of the United States Department of Agriculture 
since June, 1920, has been retained in that position by Secretary 
Wallace. 

D. YY. Frear, formerly connected with the Greenville, Tex., field 
station of the Bureau of Plant Industry, is now extension specialist 
in held crops at the University of Missouri. 

R. B. Lowry is associate professor of soils at the University of 
Tennessee, instead of instructor in soils as stated in the February 
Journal. 

Edwin T. Meredith, who has been Secretary of Agriculture since 
February, 1920, was tendered a farewell reception by about 600 of 
the scientific and technical employes of the Department of Agricul- 
ture on February 16. Mr. Meredith was presented with a bound 
volume containing an expression of the appreciation of these men for 
the interest in and understanding of their work manifested by him 
during his term of office, and of their regret that his stay in the De- 
partment was of necessity so short. This appreciation was followed 
by the signatures of the technical workers concerned. 

Charles E. Thome, who lias been director of the Ohio Agricultural 
Experiment Station since June, 1887, has resigned the directorship, 
but will remain in charge of the investigations in soil fertility. C. G. 
Williams, who has been agronomist of the station since 1902 and 
associate director since \<)\/, has been appointed acting director. 

Henry ( *. Wallace, editor of Wallaces' Farmer, Des Moines, Iowa, 
and a graduate of Iowa State College, lias been named by President 
Harding as Secretary of Agriculture, succeeding Edwin T. Meredith, 
owner of Successful Farming, also of Des Moines. Mr. Wallace was 
for a time a member of the faculty of Iowa State College, but has 
tor many war- been engaged in editorial work on Wallaces' Farmer 
and for the past several years has been its managing editor. lie has 
been active in progressive movement- for the benefit of farmers and 
t'rc|ii( nt adviser of President Harding on agricultural matters 
during the recent campaign. 



AGRONOMIC AFFAIRS. I33 

C. W. Warburton, agronomist in the Bureau of Plant Industry, 
has been detailed by the Secretary of Agriculture to supervise the 
field work in connection with the making of seed loans to farmers in 
the drouth-stricken districts, out of the $2,000,000 fund authorized 
by the appropriation act for the Department of Agriculture approved 
March 3, 192 1. Mr. Warburton left Washington March 12 to estab- 
lish a temporary office at Fargo, N. Dak., where applications for 
loans will be received. The general supervision of this activity in 
Washington is vested in a committee, of which L. M. Estabrook, 
chief of the bureau of crop estimates, is chairman. 

N. E. Winters, wiho has been engaged in graduate study at Cornell 
University for the past several months, is again located at Charlotte, 
N. C, in extension work for the North Carolina A. & M. College. 

The appropriation act for the Department of Agriculture for the 
fiscal year beginning July 1, 192 1, approved March 3, 1920, contains 
few new features or marked changes. It provides for two new super- 
visory officers, a director of scientific work and a director of regula- 
tion, at $5,000 each. In general, the appropriations for agronomic 
work are practically the same as those of the current year. An un- 
usual feature is the $2,000,000 appropriation for seed loans to farm- 
ers, referred to above. 

MEETING OF THE NEW ENGLAND SECTION. 

The seventh annual meeting of the New England section of the 
American Society of Agronomy was held at the Parker House, Bos- 
ton, Mass., Nov. 13, 1920. The meeting was presided over by Prof. 
W. L. Slate, Jr., president of the section. Those present included 
Profs. Slate, Dorsey, and Owens of the Connecticut Agricultural 
College; Prof. G. E. Simmons of the University of Maine; Prof. M. 
Gale Eastman of the New Hampshire State College; and Prof. A. B. 
Beaumont and Mr. C. G. Crocker of the Massachusetts Agricultural 
College. The program included papers on the teaching of soils and 
field crops and reports on the fertility school for county agents, ex- 
tension workers, and agronomists, which was conducted at the Rhode 
Island College in August, 1920. Most of the time was spent in dis- 
cussing teaching problems met in the introductory courses in soils 
and field crops. Prof. W. L. Slate, Jr., of Connecticut, was reelected 
president, and Prof. A. B. Beaumont, of Massachusetts, was elected 
secretary. 



1^4 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

ASSOCIATION OF SOUTHERN AGRICULTURAL WORKERS. 

The twenty-second annual convention of the Association of South- 
ern Agricultural Workers was held at Lexington, Ky., February 
15-17, 1 92 1. General sessions were held in the mornings, while the 
various sections met in the afternoon and evening. Section I, Field 
Crops and Fertilizers, of which Prof. George Roberts of the Uni- 
versity of Kentucky was president and Prof. R. Y. Winters of the 
North Carolina A. & M, College was secretary, met on February 15 
and 16. The section voted to organize as the Southern Section of 
the American Society of Agronomy, and this action was heartily ap- 
proved by the general association. The following program was 
presented : 

Factors in Crop Production Affecting the Efficiency of Fertilizers — Dean 
C. B. Williams, chief, division of agronomy, North Carolina Agricultural Ex- 
periment Station. 

Ten Years of Experiments on Methods of Cultivating Corn — Prof. E. J. 
Kinney, agronomist, University of Kentucky. 

Field Comparisons of Phosphatic Materials — W. F. Pate, soils agronomist, 
North Carolina Agricultural Experiment Station. 

Report of the Committee on Coordinating Soil Fertility and Field-Crop 
Work in the South — Prof. G. F. Kidder, agronomist and assistant director, 
Louisiana Agricultural Experiment Station. 

Ten Years' Selection of Light and Heavy Cotton Seed — Prof. E. F. Cauthen, 
agriculturist. Alabama Agricultural Experiment Station. 

The Prevalence of Corn Root-Rot and Selection for Resistance as a Means 
of Control — Dr. W. D. Valleau, University of Kentucky. 

The Place of Sweet Sorghums in Southern Agriculture — M. W. Hensel, 
C. S. Office of Sugar Plant Investigations and North Carolina Agricultural 
Experiment Station. 

Results of Various Methods of Combined Planting of Corn and Soybeans — 
Prof. K. J. Kinney, agronomist, University of Kentucky. 

Tobacco Root-Rot and Selection for Resistance — Dr. W. D. Valleau and R. 
II. Milton, University of Kentucky. 

Effect of Fertilizer on Germination and Seedling Growth — Prof. M. E. 
Slu-rwin. head of soils department, North Carolina State College. 

Some Outstanding Results from Our Cotton Inheritance Studies — Dr. R. Y. 
Winters, agronomist in plant breeding, North Carolina Agricultural Experi- 
ment Station. 

The Influence of High and Low Far, Long and Short Shuck, and Loose and 
Tight Shuck, on Yield of Corn - Dr. II. B. Brown, plant breeder, Mississippi 
Agricultural Experiment Station. 

Length ind Strength of Cotton Fiber as Affected by Place Effect — H. F. 
O'K'Ily. assistant agronomist. Mississippi Agricultural Experiment Station. 

The Value of Physical Character in the Selection of Seed for the Control of 
( om Root-Rot. Dr. W. I). Valleau and E. N. Fergus, University of Kentucky. 



AGRONOMIC AFFAIRS. 



135 



WESTERN CANADIAN SOCIETY OF AGRONOMY. 

The first regular annual meeting of the Western Canadian Society 
of Agronomy was held at the University of Alberta, Edmonton, 
December 28-30, 1920. The sessions were attended by representa- 
tives of Alberta College of Agriculture, Manitoba Agricultural 
College, Saskatchewan College of Agriculture, Alberta Department 
of Agriculture, the several Alberta Schools of Agriculture, the Cen- 
tral Experimental Farm, the Dominion Experimental Farms, the 
Dominion Seed Branch, and by several men interested in agronomy 
who have no official connection. The meeting was an enthusiastic 
one, and a considerable number of new members was added. The. 
object of the Society is to encourage investigational work in soils 
and crops and to disseminate knowledge concerning these subjects ; 
to obtain the highest standard of instruction in agronomy at the 
agricultural institutions in the prairie provinces ; and to unify and 
standardize as much as possible the methods used by investigators in 
this district. The following papers were presented : 

Scope and Arrangement of Studies in the Degree Course in Agronomy, by 
T. J. Harrison, professor of field husbandry, Manitoba Agricultural College. 

The Distribution of Studies in the Degree Course in Agriculture, by R. New- 
ton, assistant professor of field husbandry, Alberta College of Agriculture. 

The Technique of Field Husbandry, by Manley Champlin, professor of field 
husbandry, Saskatchewan College of Agriculture. 

The Past, Present, and Future of Field Crop Experimentation, by M. J. 
Tinline, superintendent of the experimental farm, Scott, Sask. 

The Place of Research in Agriculture, by Dean E. A. Howes, Alberta Col- 
lege of Agriculture. 

The Biologic Strains of Stem Rust in Western Canada, by Miss Margaret 
Newton, Saskatchewan College of Agriculture. 

Drought Resistance of Farm Crops, by E. S. Hopkins, Central Experimental 
Farms. 

Soil Drifting in Manitoba, by J. B. Ellis, instructor in crop management, 
Manitoba Agricultural College. 

Soil Drifting in Saskatchewan, by R. Hansen, professor of soils, Saskatche- 
wan College of Agriculture. 

Soil Drifting in Alberta, by W. H. Fairfield, superintendent of the experi- 
mental farm, Lethbridge, Alta. 

Methods of Breeding in Forage Plants, by Dr. M. O. Malte, Central Experi- 
mental Farm. 

A Study of the Influence of the Root System in Promoting Hardiness in 
Alfalfa, by Prof. W. Southworth, Manitoba Agricultural College (read by J. 
H. Ellis). 

Methods of Distributing Pure Seed in Alberta, by G. H. Cutler, professor of 
field husbandry, University of Alberta. 



I36 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Education Takes the Field, by E. A. Ottewell, extension department, Uni- 
versity of Alberta. 

The Effect of Premature Harvesting on the Wheat Kernel, by Dr. Charles 
E. Saunders, Central Experimental Farm. 

Symbiotic Nitrogen Fixation by Leguminous Plants with Special Reference 
to Bacteria Concerned, by R. Hansen, professor of soils, Saskatchewan Col- 
lege of Agriculture. 

Soils of the Peace River - District, by Dr. F. A. Wyatt, professor of soils, 
Alberta College of Agriculture. 

The Quality of Silage Produced in Barrels, 1 by R. Newton, assistant pro- 
fessor of field husbandry, University of Alberta. 

The need for careful research in advance of instruction and ex- 
tension was urged by President Tory of the University of Alberta at 
a banquet tendered to the members of the association by the uni- 
versity. This need was also emphasized by Dean Howes in his paper, 
" The Place of Research in Agriculture." Dean Howes, however, 
cautioned against the extreme modesty or conservatism which with- 
held results from the public and thus curtailed the benefits of research. 

Officers elected for the year 1921 are as follows: Prof. T. J. Harri- 
son, Manitoba Agricultural College, president; Prof. G. H. Cutler, 
University of Alberta, vice-president ; Prof. R. Hansen, University 
of Saskatchewan, secretary-treasurer; and F. S. Grisdale, principal 
Olds Agricultural School, and W. C. McKillican, superintendent 
Brandon Experimental Farm, additional members of the executive 
committee. 

Arrangements were made with the Alberta Department of Agri- 
culture to publish the papers presented at the meeting, and those of 
general interest to farmers will also be published iii bulletin form. 
A limited numbers of copies of the proceedings will be available to 
members of the American Society of Agronomy, who can obtain 
further particulars by writing to Prof. G. H. Cutler, University of 
Alberta. Edmonton, Alta. 

1 This paper was published in Jour. Amkr. Sue. A<;ron., v. 13, no. 1, p. 1-11. 
1921.— Ed. 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. Apbil, 1921. No. 4 



THE NATURE OF SOIL ACIDITY WITH REGARD TO ITS 
QUANTITATIVE DETERMINATION. 1 

W. H. MacIntire. 2 

It is probably true that, in recent years, no one phase of soil chem- 
istry has received more attention than the problem variously referred 
to as lime requirement, soil acidity, or lime absorption coefficient. 
The problem can hardly be considered, however, as having solely a 
chemical or physico-chemical basis in its relation to soil fertility, for 
it is closely correlated with, if not inseparable from, both bacterio- 
logical and plant physiological considerations. Until very recently, 
if even now, little effort has been made or opportunity offered for 
concerted, authentic action to clarify this intricate problem and to 
adopt terms or phrases which convey a definite and accepted meaning 
of the several possible causes and the possible differential intensities 
of these reactions responsible for the soil condition known most com- 
- monly as acid. 

Lime requirement for what? For effecting a chemically neutral 
or near-neutral condition as determined by some arbitrary chemical 
procedure in the laboratory ; for optimum biological development, as 
recorded in the laboratory ; or for maximum growth of certain spe- 
cific and responsive plants in pots, cylinders, or plats ? Some of these 
L considerations were advanced by the writer to the Association of 
Official Agricultural Chemists at its 19 16 meeting in a paper entitled 

1 Contribution from the University of Tennessee Agricultural Experiment 
Station, Knoxville, Tenn. Presented at the thirteenth annual meeting of the 

" American Society of Agronomy, Springfield, Mass., October 19, 1921. 

2 Soil chemist, University of Tennessee Agricultural Experiment Station. 

137 



I38 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



" Status of the Problem of Lime Requirement" (40) . 3 At that time, 
that Association recognized the problem, which has since been studied 
collaboratively under the Association's referee system. 

The problem of the causes responsible for the genesis and con- 
tinued occurrence of the acid characteristics in soils is admittedly a» 
complex one. The trend of the investigations has probably often 
followed lines suggested by conceptions and hypotheses, as assumed 
by various workers. These several concepts have been made of 
record and reflected by the several methods advanced for the qualita- 
tive and quantitative determinations of the total, as well as the sup- 
posedly more active and less active fractions of the total acidity. In 
the past, the study of so-called " soil acidity " took direction largely 
from the isolated and academic viewpoint of the laboratory worker 
seeking to establish reactions and to determine their speed and extent. 
Nevertheless, in much of the more recent work, special emphasis has 
been placed upon correlations with bacterial and plant-response fac- 
tors. It is the purpose of this paper to offer briefly the chronological 
development of most of the viewpoints and hypotheses advanced and 
conclusions maintained, with or without subsequent modification, by 
those who have reported upon this interesting and absorbing topic. 

The beginning of the studies wherein it was shown that siliceous 
admixtures, including soil, could effect the removal of solutes from 
solvents might be assigned to the year 1739 when it was determined 
by Hales (23) that sea water, after percolation thru stoneware, was 
deprived in part of its several salts. Probably it is better to date 
from the work of Way (71), who showed, in 1850, that combinations 
of strong bases with both weak and strong acid radicals would be 
disrupted when their neutral aqueous solutions were allowed contact 
w ith soils. The fact that potassium, sodium, calcium, and magnesium 
salts of several acids would be disrupted, thru adsorption of the basic 
radical-, and that the liberated acid radicals could be leached, has 
B I rved a- the basis of certain types of quantitative analytical pro- 
cedure. The further fact that the degree of dissociation, as in- 
fluenced by the relative Strength of a base when combined with acid 
radicals of different strength, governs both the speed and ultimate 
extent "I the basic i<>inc absorption phenomenon, has further served 
for amplification of methods, by which it is sought to deter- 
mine the differential occurrence of acids or acid properties of varying 
" avidity." 

It bai been universally recognized that, whether the acidity of soil 
k'f'ninc Ijn mimiicr is to "Literature cited," p, 15K. 



macintire: nature of soil acidity. 



139 



is to be attributed to true acids, acid salts, or solids possessing absorp- 
tive and acid-indicating properties, the causative substances are so 
insoluble as to preclude the possibility of their appreciable extraction 
by distilled water leaching when measured by the ordinary chromo- 
phoric indicator. On the other hand, such separation could not be 
effected by the use of carbonated distilled water, in simulating free 
soil water, for the basic materials brought to the solution from the 
concentrated film water and by hydrolysis of the various alkali sili- 
cates, and more particularly the alkali-earth silicates, would effect an 
immediate neutralization of any dissolved acid. Hence, the quanti- 
tative methods developed have been directed toward various reactions 
brought about during contact of soil and treatment followed by a 
quick recovery and determination of the leached or evolved end- 
products of the reaction so indicated. 

The most commonly known qualitative method of determining a 
soil's reaction is that which utilizes litmus paper. YVahnschaffe (70) 
appears to have been the first to use litmus paper as a qualitative 
means of detecting an acid condition in soils. 

Van Be-mmelen (5) was a pronounced advocate of the theory of 
adsorption by the colloidal materials characteristic of acid soils. He 
believed that substitution for liberated bases occurred in equivalent 
ratios, a conception not substantiated when applied to treatment of 
soils with CaCO s and AlgCO... It was van Bemmelen's belief that 
silicic acid, colloidal silicates, iron oxids, and humic materials are 
responsible for the indications of acidity as obtained by the pro- 
cedures involving treatments with solutions of neutral salts. 

Halleman (24) measured the readiness with which calcic com- 
pounds suffered hydrolysis when treated twenty-four hours with 
saturated carbonated water, as an indication of the need of a soil for 
basic additions. 

Tacke (60), conceiving the acidity of soils to be due to the presence 
of a true acid, used the C0 2 liberated from an agitated mixture of 
soil and CaCO s , in an atmosphere of hydrogen, as an index to " lime 
requirement." The continuity of evolution of C0 2 under long- 
continued contact, however, was not emphasized by Tacke. 

Wheeler. Hartwell. and Sargent (72), in an effort to evolve a sim- 
ple titration procedure, utilized X-10 ammonium hydroxid for treat- 
ment and determination of the excess unfixed, or unneutralized, after 
a period of contact extending over forty-two hours. These workers 
also reported their studies relative to the quantitative liberation of 
C0 2 from distilled water suspensions of CaCO s with soil, in a manner 



140 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



similar to that employed by Tacke, and pointed out the influence of 
time upon the speed and ultimate extent of the reaction. They like- 
wise studied the same procedure when heat was introduced, as was 
later done by Ames and Schollenberger (2), tho the latter workers 
used decreased pressure to low r er the boiling point. 

Yeitch (67) advanced a procedure for the determination of the 
acid properties of the soil, using the principle of effecting an equi- 
librium between the acid materials and the minimum of dissolved 
Ca(OH) 2 capable of indicating alkalinity, by use of phenolphthalein 
as an indicator, after contact with the soil. It was his belief that by 
such treatment the " total apparent acidity " could be determined. 
This "total apparent acidity'' he attributed as being "due almost en- 
tirely to insoluble organic acids and to absorption by the non-acid 
materials." In this and later work, consideration was given to corre- 
lation between laboratory findings and field results. Veitch wrote : 

While the reaction affects the chemical and the physical condition of the soil 
to a considerable extent, the growth of plants is more directly affected by the 
action of the acid on the plant roots and upon the micro-organisms of the 
soil. . . . Even very acid soils will, on long-continued treatments with much 
water, yield an extract which, on concentration, will give an alkaline reaction 
with this indicator (phenolphthalein). 

Hopkins, Knox, and Pettit (29) offered a quantitative method 
based upon the liberation and factoring of the amount of HQ (or 
FeCl 3 or A1C1 8 ) found as a result of the contact of soil suspensions 
with sodium chloride solutions. Chemical equivalence was assumed 
in the conversion of the absorption coefficient to terms of CaCO s . 
These investigators stated : 

The acids of the soils are themselves very difficultly soluble and it is prac- 
tically impossible to completely extract them from the soil with distilled water, 
even though large quantities of water be percolated through the soil; but, 
when a mineral salt solution is added to the soil, the acid apparently unites 
with the mineral base, evidently liberating the mineral acid, or an acid salt 
which, of course, is perfectly soluble, and whose titrating power furnishes a 
very satisfactory basis for determining the total acidity of the soils. 

Potassium nitrate was later substituted for sodium chlorid. 

In commenting upon the Hopkins method at the time of its pres- 
entation and referring to bis own method previously submitted for 
publication, Veitch (68) stated: 

It seems to me that the first thhiK we need to do is to define acidity and 
wttle upon an indicator winch shall be the standard by which to judge the re- 
a'ti',11 of -oils. Many of the acids that may be present in soils are so weak 
that they ^ivr in. rertain reaction with most indicators, except in concentra- 
tions greater than probably exist in most acid soils. 



MACINTIRE : NATURE OF SOIL ACIDITY. 



In a further valuable and fundamental contribution to the subject, 
Yeitch (69) studied the method of Hopkins in parallel with his own. 
He concluded that the acidity generated by the Hopkins method was 
due, in the main, to aluminum chlorid. He further concludes that 
" acid organic matter " has not been shown to liberate equivalent 
amounts of free mineral acids. Yeitch attempted to correlate the 
partial or complete neutralization of " apparent acidity " with varia- 
tion in crop yields and was of the opinion " that we are dealing with 
several kinds of ' acidity." which effect fertility very unequally." 
Yeitch differentiated between " active or actual acidity " due to rela- 
tively soluble organic and inorganic acids and salts ; and " inactive or 
negative acidity reaching in some soils to actual neutrality, as deter- 
mined by the usual indicators." The latter acidity he attributes pri- 
marily to " easily attacked hydrated or colloidal silicates and many 
non-acid organic compounds " possessing basic affinity. Veitch con- 
cluded that "We may determine the total occurrence of acidity by 
the lime water method and by subtracting the acidity determined by 
the sodium chloride method, we have acidity due to insoluble organic 
matter." 

Cameron and Bell (11) offered researches demonstrating that 
physical absorption could effect liberation of free acid thru selective 
attraction for the basic ion in a neutral aqueous medium. Along with 
other interesting analogies, they demonstrated that carefully treated 
cotton would absorb the base from filter paper, previously impreg- 
nated with a neutral litmus solution. From this observation they 
concluded that the acidity indicated by the litmus paper test may not 
represent native free soil acidity. 

Knisely (34) recommended the use of litmus paper as a qualitative 
procedure for determining "the acid condition of the soil (which) is 
due to a lack of basic substances." 

Sullivan (59) repeated the earlier experiments of Kohler (1903) 
and corroborated the findings as to the ability of acid soils to liberate 
hydrochloric acid from neutral solutions of sodium and magnesium 
chlorids ; but Sullivan attributed the acidity found to the presence of 
ferric and aluminic chlorids, which readily hydrolyze in dilute aqueous 
solution. 

Patten and Waggaman (48). without advancing a method of their 
own, published an exhaustive compilation of the researches upon the 
absorptive properties of soils and siliceous materials for both solids 
and gases. This work is of interest because of its bearing upon the 
fundamental principles involved in the adaptation of the neutral solu- 



142 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



tions of the several salts, which have been used for contact treat- 
ments and acid liberation by a number of workers. 

Siichting (58) assumed that the soil and CaC0 3 contact treatment 
employed by Tacke resulted in some decomposition of organic matter, 
with CO a liberation, which he believed should not be ascribed to acid- 
ity. He modified Tacke's procedure by discarding the C0 2 liberated 
from the soil and agitated carbonate mixture, following this step by 
determining the residual carbonate and assuming the difference be- 
tween initial and residual to be attributable to decomposition effected 
by true soil acids. 

Blair and Macy (7) used the Yeitch procedure in a study of Florida 
soils. It was their belief that the major portion of the acidity en- 
countered was due to the formation of organic acids in the soil. 

Stoddart (57) studied the parallel between soil acidity and poverty 
of phosphate soluble in N/5 HNO s and endeavored to establish a 
" causal relationship." His explanation of the parallel was: 

The soil acid acts upon the readily available phosphates, such as the calcium 
phosphates, at a more rapid rate than the normal neutral and alkaline soil 
moisture, and when once in solution these phosphates are readily washed out 
by the heavy rains, or are fixed by iron and aluminum compounds, that is, pre- 
cipitated and rendered unavailable as insoluble iron or aluminum phosphate. 
This paucity of phosphates soluble in N/5 HNO3 is a measure of acidity or its 
detrimental residual effects. 

This conception is of interest when contrasted with the later work 
on aluminum toxicity and its elimination by phosphatic manures as 
reported by Hartwell and Pember (26), Conner (14), and Mirasol 
(43)- 

Baumann (4) reported findings which led him to the conclusion 
that the acidity characteristic of peats is to be attributed to absorption 
by organic colloidal materials. 

Lipman (36) suggested the possibility of determining the intensity 
< [ soil acidity by measuring the depressive influence of added soil 
Upon biological activities in culture media. 

Hopkins (28) wrote, "Usually these soil acids exist in part, at 
least, as organic acids," hut he found that even were all of the organic 

carbon of the subsoil in the form of "humic" acid, it would be equal 

to leSfl than half of the acidity found and in some cases but one-sixth 
of the amount determined. Further, 

And lilicatcs former] from polysilieatcs. from which some basic element may 
have been removed and replaced with acid hydrogen, by reaction with soluble 
organic acids, or possibly by long continued weak action of drainage water 
d with carbonic acid, do exist in the ^>il and the evidence thus far se- 



MACINTIRE I NATURE OF SOIL ACIDITY. 



143 



cured indicates that they account for most of the acidity of soils that are, at 
the same time, strongly acid and very deficient in humus. 

Hopkins further states, somewhat at variance with other previous and 
subsequent opinions, 

The legume plants themselves are not so sensitive to acid conditions, but, 
rather, the bacteria depended upon to furnish nitrogen ; . . . 

Gregoire (22) assumed that free soil acids would liberate iodine 
from Kjeldahl's solution (KI, KIO s , and Na 2 S 2 3 ) and that the re- 
sidual thiosulfate determination would serve as a measure of the 
extent of the reaction. (It should be noted that the readily hydro- 
lyzed salts of iron and aluminum will function in like manner.) 

Bizzell and Lyon (6) made a study of the method of Albert (3), 
who proposed the distillation of ammonia from an addition of am- 
monium chlorid and a definite amount of Ba(OH) 2 , upon the assump- 
tion that the excess of barium hydrate above the amount absorbed by 
the soil would liberate a chemical equivalence of NH 3 . These work- 
ers found that soils boiled with NH 4 C1 would yield free ammonia 
when otherwise untreated, and they further established the fact that 
the maximum absorption of barium hydrate requires time and heat 
rather than being immediately effected and upon this basis they ad- 
vanced a modification. They are of the opinion that " The true na- 
ture of the acidity is not understood." 

Moulton and Trowbridge (44) studied the results offered by Biz- 
zell and Lyon. They contend that the data secured in their studies 
" seems to establish the fact that the lime requirement found by the 
method of Bizzell and Lyon is proportionate to the Ba(OH) 2 used 
and not to the acidity of the soil." 

Jones (33) advanced a procedure wherein the extent of removal of 
calcium from an aqueous solution of calcium acetate, when factored 
through empirical means, was taken as an index of lime absorption. 

Coville (16) tested samples of humifying leaves and green manures 
and noted that they are acid and that they impart to soils an acidity 
or base deficiency in the incipient stage ; but he points out the reme- 
dial residual effect of the basic elements held by the readily oxidized 
organic acid radicals. In this connection it might be well to mention 
the well known tendency of barnyard manure to maintain alkalinity 
or neutrality in a soil in a greater measure than could be attributed 
to the added calcium or other basic elements. 

Parker (46, 47) concluded that free acidity results temporarily 
when fertilizers such as KC1 are added to a soil, as a result of the 



144 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



hydrolysis of KC1 and the adsorption of the basic ions (KC1 + 
HOH±^KOH (absorbed) and HC1) ; the free acid, however, being 
quickly combined with native soil alkali earth bases or, in their ab- 
sence, with the amphoteric elements, particularly iron and aluminum. 

Abbott, Conner, and Smalley ( I ) encountered a somewhat unusual 
condition in studying soils of high organic content and low alkali- 
earth content. They found toxicity and excessive nitrification, coin- 
cident with sterility, and a soil solution excessively acid due to the 
presence of aluminum nitrate. Tho no acid other than that combined 
with aluminum was found, nevertheless the effect was that of free 
acid, an excess of H-ions, due to hydrolysis of aluminum nitrate. 

Loew (37) used the liberation of iodine from a boiling solution of 
potassium iodide in contact with soils as an indication of an acid con- 
dition. Loew is of the opinion that the so-called acidity may be due, 
in part, to " humic acid,'' but that the preponderating acidity of the 
clay soils in Porto Rico is due to mineral compounds. He believed 
that " pure clay behaves like an acid," for which he suggests the des- 
ignation " argillic." Loew suggests the use of aqueous solutions of 
sodium or potassium acetate in soil contact and the determination and 
calculation of the liberated acid in the filtrate to CaC0 3 equivalence. 

Following a study based upon KC1 absorption studies, Daikuhara 
(17) concluded that the acidity indications from humic acid were 
meager and he stressed the colloidal properties of iron and aluminum 
compounds. 

In studying the influence of some organic acids, possibly formed 
from incorporated green manures and also added c. p. organic acids, 
Temple (61) concluded "that the danger of soil injury in this manner 
is very small." 

Maclntire, Willis, and Hardy (41) found a wide variation between 
the amount of acidity indications when judged by the differentials be- 
tween the chemical equivalences of CaCCX and MgCO a absorptions 
and carbonate decompositions. They further determined that the 
neutralization of the lime requirement indications obtained by the 
Veitch procedure would not inhibit extensive further fixation of 
Mg< ( ' : and thai strong .alkalinity induced by an 8-ton CaO equiva- 
lent of MgCO gl above the \ eitch indication, would not preclude a 
further extensive fixation of MgO >... Similar findings were likewise 
obtained when using Bands, silt. clay, and kaolin, wherein the organic 
matter factor was eliminated. These investigators ignited siliceous 
.-'iid titanic materials with excesses ( ,f (aCO, and MgCO., for periods 
of * and l6 hours and then restored the moisture condition, after 



MACINTIRE ! NATURE OF SOIL ACIDITY. 



145 



which contact was permitted during a period of 133 days. The fact 
that such preliminary treatment with subsequent contacts was fol- 
lowed by the evolution of C0 2 from the added carbonates led these 
workers to conclude that silicic acid was the only acid material to 
which true acidity could be attributed, in these instances. 

Harris (25) made a number of parallel experiments with soils and 
kaolin, wherein practically no organic compounds were present. His 
results led him to the conclusion that " The behavior of the soil 
towards neutral salts is not due to the presence of insoluble organic 
acids, or even to the presence of organic matter at all, but to inorganic 
compounds, probably hydrated silicates." Harris further showed 
that sodium was absorbed by the soil and kaolin in distinctly different 
amounts, according to its combined acid radical, when odded in molar 
equivalence and equal concentration. Because of this, he pointed to 
the unreliability of the " results of analytical methods for determin- 
ing the * lime requirement ' of a soil, unless the method employed be 
the material that is to be used in the field." 

Hutchinson and McLennan (32) believed that, since in most liming 
operations the absorption or neutralization of the carbonate proceeds 
thru action of calcium bicarbonate upon the acid soils, it would seem 
logical to treat the soil with this solution. They permitted contact 
of suspended acid soil with calcium bicarbonate of definite strength 
for a definite period. After filtration the determination of residual 
bicarbonate was carried out by direct titration. These workers sup- 
plemented their laboratory investigations with pot studies and believed 
that they were able to establish some correlation. 

HAMacIntire (38), carrying out the same thought, evaporated soil 
with a definite amount of CaH 2 (C0 3 ) 2 and determined the C0 2 of 
the precipitated residual CaCO s . He pointed to the fact that this 
method, insofar as he could establish, would give definite laboratory 
results capable of close checking, but that the procedure did not 
record the continued propensity of the soil to effect decomposition of 
calcium carbonate. This continued reaction between soil and alkali- 
earth carbonate, as demonstrated by laboratory and field results, is 
one which may extend over a period of years. 

Truog (62) advanced a qualitative test based upon the liberation 
of H 2 S from zinc sulfid when boiled with acid soil, particularly when 
the reaction is accelerated by the absorption of calcium and liberation 
of HC1 from simultaneously added CaCl 2 . To this procedure he 
accredits the faculty of the determination of acidity in an approxima- 
tion to the quantitative requirement of practice. In a supplement to 
his bulletin Truog states : 



I4& JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The acids causing soil acidity vary greatly in strength. Some soils contain 
considerable amounts of acid which are so weak that they cause little injury. 
For this reason an absolute quantitative method does not indicate the amount 
of lime which should be used. 

Lint (35) studied the increase of lime requirement in leached soil 
cultures in the laboratory, as induced by addition of flowers of sulfur, 
using the Tones acetate procedure as a measure of changes induced. 
It appeared from his results that the alkali-earth bases had combined 
with the sulfuric acid engendered and that the decrease in the native 
store of these elements was responsible for an increased absorption 
of lime from the added calcium acetate used in making the deter- 
mination. 

Clark (12) contributed a classic dissertation entitled, " The Con- 
stitution of the Natural Silicates." This treatise has intimate rela- 
tionship to soil acidity studies, since, by his interpretations, it is easy 
to comprehend how neutral or alkaline silicates may become of acid 
or base absorbing nature, thru the removal of bases by mineral acids, 
as was done by Harris, or their treatments with carbonated water, as 
was done by Truog, the writer, and others. To pure silicate forma- 
tions, Clark attributed a definite chemical structure and assigned to 
various silicates a composition representing them to be true acid salts 
of the several possible silicic combinations. 

In this connection it is interesting to note the observations of Brown 
and Johnson (10), relative to the influence of grinding upon the indi- 
cation secured thru the use of the Veitch procedure. These workers 
reported that the finely ground soil gave an alkaline reaction as com- 
pared to an acid condition indicated prior to grinding. This would 
be expected in the case of new soils of the glaciated regions where 
grinding would disrupt undisintegrated particles, yielding fresh sur- 
faces or mere readily hvdrolizable compounds; or again, where cal- 
rite or similar materials might be included within quartz crystals. 
( hn the other hand, working with highly siliceous soils, Cook (14) 
found thai grinding increased acidity. This is in harmony with the 
findings of Maclntire, Willis, and I lardy (41) previously mentioned, 
in which it was shown that pure quartz sand would decompose CaC0 3 
and M^CO.. -oinewhat in proportion to the fineness of the siliceous 
material. 

Ruprechl and Morse (52) conclude thai the acid condition of soils 
brought about by the use of ammonium sulfate is not due to the 

Cumulation of free acid; thai the sulfuric acid engendered from 

treatment* results primarily in effecting a lime deficiency; and 



MACINTIRE I NATURE OF SOIL ACIDITY. 



147 



that upon depletion of lime salts the excess of acid combines with iron 
and aluminum, forming sulfates of these elements which impart 
acidity and toxicity to the soil. 

In studying the ammonium-sulfate-treated plats of the Pennsyl- 
vania station, White (73) concluded that an assumed increase in 
occurrence of " humic acid " is responsible for the increased acidity 
of these plats, as measured by the procedure of Veitch (67). White 
also offers certain refinements as modifications of the Veitch pro- 
cedure. 

Frear (18) offered a comprehensive treatise upon " Sour Soils and 
Liming " in which a general review is offered of the causes attrib- 
uted as being responsible for the occurrence of acid soils. He con- 
cludes that the investigations reported justify the conclusion "that 
the acid-acting substances are probably numerous rather than few 
and simple." 

Gillespie (19) conceded that the total amount of acidity present is 
an important factor, but gives consideration to the intensity of the 
acidity, i.e., H-ion concentration, for the determination of which he 
used the hydrogen electrode and the colorimetric procedure of Lubs 
and Clark. 

Maclntire (39), in reporting upon the factors that influence lime 
and magnesia requirements of soils, showed that alkaline kaolin 
('alkaline to litmus) and clay would evolve C0 2 from moist contact 
treatments of CaC0 3 and MgCOo, particularly the latter, and that 
pure quartz and rutile (Ti0 2 ) would affect the same evolution both 
at low temperature over long periods and upon short periods of boil- 
ing. Emphasis was also given to the fact that silicates of calcium 
and magnesium formed from contact of excess of Si0 2 , or silicates, 
with the alkali-earth carbonates could readily be decomposed, if the 
condition of the active mass were reversed ; i.e., when the silicates 
were treated with carbonated water. It was also shown that pre- 
liminary treatments with sodium hydrate, followed by leaching, and 
oxygen combustion of alkaline earth did not preclude further decom- 
position of alkaline earth carbonates, as measured by C0 2 evolutions, 
when moist contact was permitted for periods of 133 and 473 days. 
Differentiation was further made between the immediate decompo- 
sition of CaCO, and MgC0 3 by soils and the continued decomposi- 
tion, as evidenced by the Pennsylvania and Tennessee data. 

As a development of these studies and limiting the discussion to 
rock-derived soils, and with the conception that the term " soil acid- 
ity " denotes a soil's ability to decompose calcium carbonate, as would 



I48 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



be the conception for practical application, Maclntire advanced cer- 
tain conclusions relative to the cause and effect of soil acidity. 

First it must be emphasized that, in uncarbonated water solution, Si0 2 proves 
to be a stronger acid radical than C0 2 of earthy carbonates. The reversal of 
conditions is effected when there is present an excess of C0 2 gas. ... It is 
probably true, as indicated by data given, that both of these conditions actually 
exist at different times under field conditions. . . . That we do have free min- 
eral acid — silicic acid — in soils, is true .... this acid effects appreciable and 
long-continued decomposition of CaC0 3 and excessive decomposition of MgCOs 
and (that) its acid salts — clays — are even more acid than the relatively insoluble 
acid itself. 

This reference to acidity applied to the quantitative determination 
of the amount of acidity as recorded by the usual indicators in titra- 
tion procedures and not to the intensity factor as would be determined 
by the hydrogen ion concentration. In considering the growing plant 
in the environmet of an acid soil, it was pointed out : 

Thus we have the lime-loving plants which do not thrive, not because their 
nutrient solutions are acid,- but because the available solutions are not suffi- 
ciently concentrated in their CaCOz content, or possibly in neutral salts of root- 
formed acids which act directly upon the bases of the unhydrolyzed silicates. 
. . . It is conceivable that rapidly growing plants would extract lime and also 
other bases from the soil solution more rapidly than the soil moisture could 
effect the hydrolysis of the silicates, from which an acid soil principally derives 
the bases which are offered to the plants. 

Two years later, Truog (65) recorded what would seem to be a 
concordant, if not identical, viewpoint. The concordance extends, 
however, only thru consideration of soil supply and plant needs in an 
acid soil, since the Tennessee station offering did not extend to a con- 
sideration of the functions of the calcium salts within the plant. 
Without citing the thought set forth in the two preceding sentences 
rjnoted and presumably having failed to note it, or having considered 
it as not being equivalent or parallel to his own deductions, Truog 
1 65 I proposed a new theory. He wrote as follows: 

The supply of available calcium in all forms becomes less as soils become 
acid, (ml usually there- is still sufficient present to furnish that needed as direct 
plant food material. . . . The comparison reveals a close correspondence and. 
hence substantiates the theory, which lias been proposed, that usually the main 
Iptdfic injury of soil acidity il that it prevents plants, especially those with 
high lime requirement and relatively weak feeding powers, from getting the 
lime from the soil at a sufficiently rapid rate to meet their needs. . . . The 
expression " lime remiii nm nt " of a plant refers to the actual lime needs of the 
plant itself, especially as to the need and rate at which lime must be secured 
from the soil by the plant for normal growth. 



MAC IN TIRE I NATURE OF SOIL ACIDITY. 



149 



However, in this and in a succeeding publication with Meacham 
(66), Truog carried the reasoning further into the physiology of the 
plant and states that 

The main specific harmful influence of soil acidity on certain plants is due 
. . . to its influences in preventing these plants from getting, at a sufficiently 
rapid rate, the calcium as carbonate or bicarbonate which is needed to neutral- 
ize and precipitate certain acids in the plants themselves. ... In the life 
processes of plants, acids are formed, some of which are probably simply by- 
products. Lime and other bases are needed to neutralize these acids. . . . 
Unquestionably, in many cases, soil acidity, by limiting the supply of lime avail- 
able for plants, effects the acidity of the juice or protoplasm of these plants. 

He concludes that a sufficient supply of carbonate or bicarbonate of 
lime is essential as a regulatory component of the plant juice in main- 
taining the optimum hydrogen-ion concentration of the plant sap. 

Sharp and Hoagland (53) are of the opinion that, even with the 
presence of suspended soil particles, " Soil acidity should not be set 
apart and considered as a phenomenon unrelated to the ordinary con- 
cepts of acidity," and from their hydrogen-electrode studies they con- 
clude, " Soil acidity is due to the presence of an excess of hydrogen 
ions in the soil solution." 

Conner (13) advanced the procedure, " in which the catalysis of 
ethyl acetate is taken as a measure of the soluble soil acidity." Con- 
ner concluded that the neutralization of acid silicates is a chemical 
function, rather than a physical one, because of the evolution of heat 
incident to the neutralization. He likewise established a parallel be- 
tween the extent of hydration of clay and the amount of acidity found. 
Conner made the further interesting observation, later confirmed as 
an observation upon plant growth by Brooks, as well as by Hartwell 
and by Mirasol, that acid phosphate reduced the injurious effects of 
soil acidity. 

Truog (64), in offering a method for the quantitative determina- 
tion of the causes responsible for soil acidity, states that " The insol- 
uble nature of the soil acids must be clearly recognized in an attempt 
to devise satisfactory methods for detecting and determining them," 
and that it is "a bold assumption'' to assume "that the acids in all 
soils are of the same strength." He accordingly attempts to differ- 
entiate between the " active " and " inactive " or " latent " acidity in 
determining the total. Treatments with Ba(OH) 2 for one minute 
and then carbonation of the residual hydroxid by C0 2 , followed by 
evaporation and C0 2 -liberation determination, is the procedure em- 
ployed to determine the active acidity, while the total acidity is deter- 
mined in the same way except that the contact of Ba(OH) 2 and soil 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



is maintained at boiling temperature for thirty minutes. The " latent " 
or ''inactive" acidity is determined by difference. Truog thinks 
" that the seriousness of a soil's acidity and the urgency of the need 
of lime is not indicated by the total active acidity alone. It is neces- 
sary to also consider the avidity of the active acid." In another part 
of the same article Truog states, " From other data, although incon- 
clusive, it appears that, in upland soils, the active acidity is due largely 
to acid silicates and the latent acidity to a peculiar condition of kao- 
linites and allied compounds." In his summary, Truog states, " Soil 
acidity is due to true acids and not to selective ion adsorption by 
colloids." 

In using identical treatments as to additions, but different periods 
of contact at widely different temperatures, Truog thus arrives at the 
conclusion that the greater reaction effected at the higher temperature 
over the longer period of contact is a measure of acidity different 
from that of the shorter period of contact. However, in the pre- 
viously cited work of Wheeler and that of Maclntiie, Willis, and 
Hardy, and of others, the principle of continuous reaction was estab- 
lished and later independently confirmed by means of an entirely dif- 
ferent technic in the hands of Bouyoucos. 

In the two cited papers from the Tennessee Agricultural Experi- 
ment Station it was shown that " rutile, opal, silt, red clay, soapstone, 
kaolinite, serpentine, aluminum silicate, and oxygeii-combusticated 
residues of loam previously excessively treated (as measured by the 
Yeitch procedure | with CaCO., and MgCO s continued to effect evolu- 
tions of C0 2 from further moist contact with alkali-earth carbonates. 
J in- continued reaction was noted after progressive periods of 14, 
28, 56, 78, 133, and, in the three instances so tried, also up to 473 
day-, even tho the siliceous and titanic materials were first heated at 
white heat for [6 hour-. It is hardly conceivable that the residual 
acid-reacting substances could be other than some form of siliceous 
combination. 

Truog fftf) offered a further dissertation in which he endeavored 
to invalidate tin previously mentioned work of Cameron and also that 
of Harris, who ascribed acidity indications as being induced by se- 
lective removal of bask ion-. Truog believes selective ionic absorp- 
tion to be "questionable." lie further believes, in disagreeing with 
reverse contentions and evidence of others, that "When condi- 
KTt properl) Controlled, . . . the reactions due to soil .acidity 
take plan according to chemical equivalence. . . ." In contraven- 
tion, it mighl !»«• pointed out that carbonated water solnlions of CaCQ 3 



MACIXTIRE : NATURE OF SOIL ACIDITY. 



151 



and MgC0 3 , in excessive amounts, vary very markedly both in active 
mass and in the extent to which they undergo decomposition and fixa- 
tion with thoro contact and under field conditions, as was previously 
pointed out in the cited work of the Tennessee station. 

Bouyoucos (9) ingeniously adapted the lowering of the freezing 
point of neutral salt solutions to a study of soil acidity. His investi- 
gations apparently justify the conclusion: 

The presence of soluble acid, or acid salts, in the mineral soils under favor- 
able natural conditions is only temporary, if ever present, and never permanent. 
. . . The acidity of mineral soils appears to be due almost entirely to acid 
alumino-silicates, silicic acid and silica and (that) the mineral soils rarely, if 
ever, contain permanently free soluble acids. . . . The acidity or lime require- 
ment of the soils might be ascribed almost entirely to insoluble hydrated silicic 
acid, acid alumino-silicates, silica and organic insoluble substances, in the case 
of mineral soils; and to organic soluble acids and humus substances and organic 
insoluble acids and humus substances in the case of peats and mucks. . . . 
There appears, then, to be practically no active acidity in the mineral soils, but 
only negative. 

Bouyoucos thus differentiates, as do many others, between rock de- 
rived soils and peats and mucks. 

Rice (50) used thirty-three soils in studies upon hydrogen-ion in- 
tensities thru the use of soluble neutral salts and came to the conclu- 
sion that " Acid soils rarely contain water soluble acids ; but one case 
of mineral soil and one of muck soil was found that did yield acid to 
water." 

Ames and Schollenberger (2) published an exhaustive resume of 
the outstanding researches and viewpoints relative to soil acidity and 
its causes. They also offered comparative studies upon the Veitch, 
Hopkins, Hutchinson and McLennan, Maclntire, and their own 
" vacuum" method, which they found to give results higher than those 
obtained by the other methods. Their method is based upon the 
determination of C0 2 evolved from soil and CaC0 3 when boiling with 
reduced pressure, in order to minimize the disintegrating effect of heat 
upon organic matter. Among some of the viewpoints entertained by 
these workers we may quote : " . . . soil acidity, as the term is applied 
to the usual soil of mineral origin, is a negative property." " The 
phenomena of soil acidity are thus but symptoms of a condition — the 
lack of basic material — which is to say, poverty in basic calcium." 
And discussing the occurrence and nature of alumino-silicic and silicic 
acids, " A soil may thus give an alkaline extract and still possess con- 
siderable power to combine with bases." With this conception in 
mind, lime requirement is defined as a " soil's capacity for combina- 



152 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



tion with basic calcium," with differentiation between laboratory 
measurement and the practical problem of " optimum effects upon 
crop growth." After a summation of the various concepts they con- 
clude, "The theory of the existence of silicic. or alumino-silicic acids 
in the soil would serve as a complete explanation for all the observed 
phenomena ; the conception is simple and is supported by analogy with 
better known reactions, which is as much as can be said for any of 
the theories which have been offered." As a practical application 
they are of the opinion that " There is no evidence that any of the 
methods tested furnished reliable indications as to the optimum rate 
of application for field practice." 

Rice and Osugi (51) utilized the extent of inversion of cane sugar 
induced by contact with soil suspensions as an index to acidity. They 
found that inversion of cane sugar was induced by a soil-contact 
treatment even tho " the digestion extracts were found to be alkaline." 
Further, " There is no doubt, then, that a soil may contain an acid 
and, at the same time, enough base to neutralize this acid without this 
neutralization ever taking place," thus offering a possible explanation 
of the continued occurrence of CaCO s in intimate contact with soil 
in the field, altho equivalent MgC0 3 treatments had long before dis- 
appeared, as had been previously mentioned. By their ingenious 
method of approach, these workers established the fact that rela- 
tively " insoluble silicic acid and adsorbed acids, as well as soluble 
acid, may invert cane sugar," and in several ways demonstrated " that 
the inverting activity of soils is chiefly a property of the insoluble 
part/ 1 These findings are well correlated with the Tennessee station 
findings and conclusions that free silicic acid, as represented by quartz, 
may. in mass, effect extensive decomposition of alkali-earth carbo- 
nates and further that acid silicates, relatively insoluble, have an ex- 
tensive decomposing action upon alkali-earth carbonates. 

Stephenson (55)i m a Study of "soil acidity methods" involving 
the Hopkin-. Witch. Junes, Maelntire. Truog, and Tackc methods of 
procedure, concludes, " The activity of soil acids varies greatly as 
measured by the rate of evolution of carbon dioxide. The more re- 
active acids react at once. The less reactive only after long contact 
and thorough mixing of soil and carbonate and more complete re- 
moval of carbon dioxide liberated." 

Rummer (4^) studied the reaction of a number of North Carolina 
lOlll by the elect n. metric method of determining hydrogen-ion con- 
centration. He Mates, "It would appear that, with the excessive 
rainfall of tin- region, an accumulation of soluble acids in soils would 



macintire: nature of soil acidity. 



153 



be almost impossible." He found the reaction of the free and soil- 
film water to be identical, but of varying intensity. The concentration 
of the film-water was greater than that found in suspensions, in both 
instances, of excess of hydrogen-ion in the untreated soils and OH-ion 
for the CaC0 3 - and MgC0 3 -treated soils. He found acid phosphate 
to be negative in its effect, while NaNO s treatments augmented 
OH-ion concentration. Potassium sulfate increased H-ion concen- 
tration, but not to the extent brought about by ammonium sulfate. 

Hoagland and Sharp (27) are of the opinion that soil acidity " has 
a definite and precise meaning ; namely, the condition of the soil in 
which its aqueous solution contains H-ion in excess of OH-ion" ; and 
that " these H-ion concentrations may be definitely determined by 
measurements with the hydrogen electrode." Furthermore, they are 
of the opinion that, " lime requirement, insofar as it is related to 
soil acidity, would consist of the amount of lime necessary to bring 
the acid soil to the neutral point as ascertained by the above men- 
tioned procedure." " Such a lime requirement implies that the dis- 
solved and total undissolved soil acids have been neutralized." How- 
ever, " The reaction is so prolonged either by rate of solution of the 
soil acid, or their slow diffusion through the soil particles, that the 
point of neutrality may not seem easy to establish and maintain 
permanently." Thus, " An apparent equilibrium may be disrupted, 
owing to the solution and diffusion of the soil acid." Altho, a* cited 
in this paper, treatments of some soils with carbonated water will 
extract and yield CaCO s leachings by hydrolysis and carbonation, 
thereby enhancing the CaCO s decomposing power of the more acid 
residue of soils, these workers conclude — " The hydrogen-ion concen- 
tration of suspensions of acid soils is not markedly effected by in- 
creasing the content of carbon dioxide up to ten percent." 

As seemingly in contradiction to this conclusion, Noyes and Yoder 
(45) found that, "Carbon dioxide added to cropped soil (not suspen- 
sions), treated with lime alone, or lime and fertilizer, increased its 
acidity," as indicated by the Hopkins method. 

Gillespie and Hurst (21 '), in continuing their hydrogen-ion concen- 
tration studies upon the solution phase of soil acidity, concluded that 
an " examination of a large number of soils from northern Maine 
showed an excellent correlation between the hydrogen-ion concen- 
tration and occurrence of common potato scab." 

Hartwell and Pember (26) studied the reason for improvement in 
growth of barley induced by lime, as contrasted with " the very little 
influence upon the growth of rye." They found that while the two 



154 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



crops reacted in close parallel to acidified nutrient solutions, they 
varied in their growth in acid soils and also in the aqueous extract 
from the same soils. These workers concluded that the presence of 
aluminum in true solution was the cause of toxicity to the barley. 
Elimination of soluble aluminum was brought about by addition of 
phosphates, as well as by lime. As a practical application of their 
findings they conclude : " The results indicate that the practical ad- 
vantage of phosphating and liming may often prove to be due to the 
precipitation of active aluminum, quite as much as to phosphorus as 
a nutrient, or lime as a reducer of acidity." 

W Tiite (74) used the Yeitch procedure as an index to changes in- 
duced by the incorporation of stable manure and leguminous and 
non-leguminous green manures. He found that acidity, as regis- 
tered by the procedure, was decreased initially, but later an aug- 
mented acidity was found, due in the main, it appeared, to nitrification. 

Howard ( 30) advanced a procedure based upon the evaporation 
of soil and of excess of ammonia at the temperature of boiling water 
and the determination of the residual ammonia, the fixation of which 
he observed was independent of the amount added, time of contact, 
and temperature of evaporation. By this worker, " It is believed 
that the ammonia retained is held chemically by a neutralization of 
either free acids, acid organic compounds or acid salts, while physical 
absorption is largely prevented." 

Conner (14) studied the changes in "soil acidity as effected by 
moisture conditions of the soils," using the Yeitch, Jones, and Conner 
methods to record changes. The acidity of the half-saturated soils 
was greater than that of the one-fourth saturated, both being greater 
than that of the original soil. Conner is of the opinion that "Pri- 
marily, -<>il acidity is due to an excess of acid reacting compounds, 
or in other words, to a deficiency of bases. This deficiency of bases 
fa caused to a large extent by the leaching of calcium and magnesium 
in the drainage water." Me stresses the potential acidity of silicic 
acid, when in a hydratcd state of combination with aluminum. 

Sharp and Hoagland 154), in repeating some of the work of Rice 
and Osugi, confirmed the Eacl thai Sin, would affect the inversion 
of cam ugar and recorded the acidity of the quartz as measured by 
the hydrogen-ion determination. The\ further contended, as op- 
po '-I to Rice, thai the water extracts of the acid soils were acid and 
dial ucti extraction! dice ted inversion of cane sugar; the extent of 

Midi reversion by BOilfl being! in a measure, a function of the intcn- 
H of the aciditN registered by the 1 1 -ion determination. 



MAC IN TIRE : NATURE OF SOIL ACIDITY. 



155 



Stephenson (56), in studying the "activity of soil acids" by the 
use of the Tacke method over various periods of time, confirms pre- 
vious observations to the effect that the reaction between carbonate 
of lime and soil is progressive and cumulative. To the presence of 
acid silicates and silicic anhydride, formed during the process of soil 
formation, he attributes the fact that " Mineral soil may have a com- 
paratively large reserve of slowly reactive acid . . . capable of a 
more or less indefinite but continuous decomposition of carbonate." 
He further points to the fact that any mineral acid, such as sulfuric, 
engendered from the oxidation of inorganic or organic sulfur com- 
pounds, or nitric acid, engendered thru nitrification, are quickly 
neutralized and eliminated by leaching. Concerning organic acids, 
he is of the opinion that " the general indication is, therefore, that 
organic matter is not likely to produce a harmful soil acidity." 

Howard (31), in studying the basicity increase incident to the use 
of nitrate of soda, as contrasted to the enhanced acidity subsequent 
to the use of sulfur of ammonia, concludes : 

The acidity of a soil caused by long continued use of ammonium sulphate is 
a result in the change of the ratio of acids to bases. The position normally 
occupied by the stronger bases, such as calcium and magnesium, has been taken 
by weaker bases, such as iron and aluminum. The neutrality of the soil solu- 
tion can no longer be maintained, since salts of these weak bases dissociate. 
Free acid, resulting from this dissociation, is accompanied by a definite con- 
centration of hydrogen-ions. 

From an investigation of the " reduction potentials of bacterial cul- 
tures and waterlogged soils " Gillespie (20) suggested the possibility 
" that 1 sourness ' of soils includes something beyond acidity and 
(that) the residual unfavorable quality may be a high intensity of 
reduction." 

In testing the reactions of a number of plats under numerous con- 
ditions, Blair and Prince (8 ) employed the Yeitch procedure as a 
quantitative index, while simultaneously observing the intensity of 
the acidity by means of colorimetric hydrogen-ion determinations. 
The relationships between initial quantity and intensity coefficients 
of untreated soil and those recorded subsequent to half -ton, i-ton, 
and 2-ton applications of limestone and dolomite were such as to 
lead to the conclusion that, " for the samples tested there appears to 
be a fairly close correlation between the hydrogen-ion concentration 
of the soil extract and the lime requirement as determined by the 
Yeitch method." 

Martin (42) found in a study of the control of potato scab through 
the use of flowers of sulfur, thereby decreasing basicity or increasing 



I56 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



acidity, that the hvdrogen-ion concentrations of water extracts were 
increased by sulfur treatments and that such an increase depressed 
the injury due to scab. Martin found a correlation between the ini- 
tial H-ion concentration and the residual as influenced in measurable 
degree by the varying amounts of sulfur treatment. He was of the 
opinion that it is both feasible and economical to regulate the sulfur 
treatments by means of an initial H-ion determination. 

Mirasol (43) studied the effect of soluble aluminum as a factor in 
soil acidity, using the modified KNO a procedure of Hopkins as a 
measure of the formation of aluminum nitrate. He reported that 
" from 44-60 percent of the aluminum in the soil may be leached out 
by potassium nitrate and that the leaching of this amount is accom- 
panied by a big decrease in the acidity." " The 40 or 60 percent of 
aluminum leached out represents these soluble compounds or active 
aluminum . . . equivalent to approximately 53,240 and 90,720 pounds 
per acre respectively.'' He discusses the harmful effect of excess of 
aluminum which may be present in the soil, as either sulfate or ni- 
trate, and confirms the previous work wherein both acid phosphate and 
lime were effective in decreasing the occurrence of soluble toxic 
aluminum salts. Instead of applying the method upon the basis of 
his statement of the original conception, "that the acids (humic 
acids) react with the salt solution, uniting with the mineral base, 
forming neutral humates and liberating the mineral acid or acid 
salt." Mirasol concludes, " In so far as aluminum is a factor in soil 
acidity, the Hopkins method is the best one for soil acidity deter- 
minations." 

Sum marv. 

The acidity of mucks and peats poor in alkali and alkali-earth bases 
can not be considered on the same basis as rock-derived soils. The 
organic contents of peats and mucks possess acid, or base fixing, 
properties. It a mooted point whether such acidity is caused by 
adsorption or by true acids. 

Considering rock-derived soils — 

1. Altho salts of a number of organic acids have been isolated from 

soils, no one definite free organic acid has ever been extracted, as 

<>! record. 

2. if all of the organic carbon in many soils was considered as being 
a constituent of a definite organic acid, the hypothetical acid so calcu- 
lated would be equivalent to only a fraction of the amount of .acidity 
determined by different methods of procedure. 

3. In practice, certain salts produce a decrease of soil acidity (so- 



MACINTIRE : NATURE OF SOIL ACIDITY. 



157 



dium nitrate, potassium nitrate, etc.), tho in the laboratory treat- 
ments during short periods followed by extractions, the reverse may 
be true ; while the addition of certain other neutral salts produced an 
increase in acidity in both laboratory and field due to removal of 
native bases or amphoteric elements. 

4. Removal, or adsorption, of dissolved bases by soils appeared to 
be a chemical function of acid silicates, principally alumino-silicates, 
the extent of whose hydration is a controlling factor in initial inten- 
sity and continuity of reaction. 

5. The acidity of soils is, in the main, induced by the loss of calcic 
and magnesic inorganic salts, derived originally from the hydrolysis 
of the alkali-earth siliceous complexes, thereby increasing the acid 
properties or amount of acid silicates. 

6. Where the base and its combined radical are added, in H 2 solu- 
tions, to soils, and in equivalence, with reference both to mass and 
degree of dissociation, the adsorption of basic ions may be considered 
as of near equivalence. But when alkali-earth carbonates (CaCO s 
and MgC0 3 ) are subjected to moist and intimate contact with acid 
soils, the active masses will vary in amount and degree of dissocia- 
tion, while the precipitated product of the reactions will vary in their 
solubility, or tendency toward reversion thru hydrolysis and re- 
carbonation ; hence, the difference in attaining and maintaining equi- 
libria and the disparity in the extent of the reactions, which will vary 
markedly from chemical equivalence in a given time. 

7. Silicic acid, in mass, will progressively hydrolyze and continue 
to decompose calcium and magnesium carbonate when the liberated 
COo is removed from solution. This acid will pass from the solid to 
solution phase yielding H-ion concentration and is capable of effect- 
ing an inversion of cane sugar. 

8. After intense alkali treatments and the removal of excess of 
hydrates and after intense heating, pure silica, silicates, and titanium 
oxid will, on the addition of H 2 0, hydrolyze and act as acids towards 
the alkali-earth bases. 

9. Many acid soils will yield aqueous extracts, alkaline to some of 
the common indicators, but showing H-ion concentration by electro- 
metric or colorimetric methods. 

10. The H-ion concentrations of acid soils .are not generally con- 
sidered as being of such intensity as to be of direct detriment to 
higher plant life, tho they may effect the growth of bacteria and fungi. 

11. The injurious effect of acidity may be attributed, in some in- 
stances, to aluminum and other toxic salts, but, in general, more par- 



I58 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



ticularly to the diminished supply of available calcium from the de- 
pleted lime content of the soil, as influencing the adaptability of the 
media for biological development and the meagerness of the lime as 
plant food, or as an essential regulatory component of the plant juice. 

12. The formation of organic acids and the generation of mineral 
acids, such as nitric, in soils may be conceded; but their occurrence 
within the soil seems to be of but brief duration, because of neutrali- 
zation by native or applied basic materials. 

13. The reactions between soils and alkali-earth carbonates are 
characterized by a more intense initial activity, with a continued and 
lesser intensity extending over a long period of time. Such varia- 
tions have been attributed to different acids, of active and less active 
" avidity," or to the greater immediate solubility and the lesser pro- 
gressive solubility of silicic acid and its acid salts. 

14. An excess of basic carbonates may occur in a soil possessing 
slow-reacting, but potential, acidity, in the form of slowly hydrolyzing 
and ionizing silicic acids and their acid hydrogen salts. 

15. And finally, tho not unanimously agreed, it seems to be the 
majority viewpoint that the laboratory determination of a soil's tend- 
ency to absorb, fix, or neutralize lime is an academic consideration, 
without any definitely established quantitative correlation with field 
practice. 

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71. Way. J. T. On the power of soils to absorb moisture. In Jour. Royal 

Agr. Soc. England, v. 11, p. 313, 366. 1850. Cited by Patten and Wagga- 
man (48). 

72. Wheeler, H. J., Hartwell, B. L., A and Sargext, C. L. Chemical methods 

for ascertaining the lime requirement of soils. R. I. Agr. Exp. Sta. 
Bui. 62. 1900. Also in Jour. Amer. Chem. Soc, v. 22, p. 153. 1900. 

73. White, J. W. The results of long continued use of ammonium sulfate 

upon a residual limestone soil of the Hagerstown series. In Pa. Agr.. 
Expt. Sta. Ann. Rpt., 1912/1913, p. 55-^02. I 9 I 4- 

74. . Soil acidity as influenced by green manures. In Jour. Agr. Research, 

v. 13, no. 3, p. I7I-I97- 1918. 



THE EFFECTS OF LIMING ON THE AVAILABILITY OF SOIL 
POTASSIUM, PHOSPHORUS, AND SULFUR. 1 



J. K. Plummer. 2 

The Effects of Liming on Soil Potassium. 

It has been known for a long time that additions of certain neutral 
salts to the soil bring about an exchange of bases between the added 
salt and those of the soil complexes. 

The mechanism of this basic exchange has been the subject of some 
conjecture. Up until the results secured by Parker (16), 3 it was 
thought that the exchange of bases was one of double decomposition 
between the soil minerals and neutral salt, the base of the soil being 
partly replaced by an equivalent of that from the salt. Parker con- 
tends that this exchange is due to the absorption of the base by the 
soil and the formation of free acid from the anion of the salt. It is 
this acid which has the solvent effect on the soil bases, most important 
of which is potassium. When this acid is neutralized by additions of 
XaOH, no potash is found in solution from additions of neutral salts 
to the soil. However, Maclntire (12) pointed out that, when the 
added salt is composed of a weak anion like CaCO :; and the base is 
absorbed, the CO... ion set free would probably behave in a different 
manner from the stronger ions of CI, S0 4 , etc. Some of the C0 2 
thus formed might escape into the atmosphere, while, on the other 
hand, the increase in concentration of HXO : , probably increases 
solution of the soil bases. 

The addition of basic calcium and magnesium compounds to the 
soil is thought by some to materially affect solution of potash from 
the inert soil mas-. 50 much so as to be of considerable practical value 
nnd( r field conditions. 

LABORATORY and POT STUDIES. 

From the following review, it can be readily seen that the subject 
of increasing the potash supply of the M,j] by additions of calcium 

1 Prevented at the thirteenth annual meeting <>f tin- American Society of 
Agronomy. Sprin^eM. Mast., Octoher 10. \<)20. Contribution from the North 
Carolina Agricultural Experiment Station. West Raleigh, N. C. 

2 Formerly <-'<il chemist, North Carolina Agricultural Experiment Station. 
•Reference is to "Literature cited," p. 170. 

J 62 



plummer: effects of liming. 



163 



and, to a lesser extent, magnesium salts has received much attention. 

The earlier investigators seem to have been impressed more with 
possibilities of gypsum rather than with those of the basic forms of 
lime. This is exemplified from the following statements from Storer 
(18), who says " that gypsum exerts a powerful action in setting free 
potash, which has been absorbed and fixed by the earth, that is to 
say, by double silicates in the earth." This writer also goes on to say 
"that gypsum sets free potash to be transferred to lower layers of 
the soil so that roots can everywhere find a store of it." 

Gaither (7) concluded from his work that little, if any, potash is 
made available by the action of lime on soils. He determined the 
potash content of wheat grown on limed and unlimed soils, showing 
that additions of lime depressed the potash content of the wheat. He 
used N/5 HNO s as the solvent for measuring the solution of the 
potash and extracted for 5 hours, the soil being Volusia silt loam, to 
which was applied lime, CaO, at rates from 2 to 26 tons per acre. 

Bradley (1) mixed three soils with 1 percent each of CaO and 
CaS0 4 , separately, and maintained 20 to 25 percent of moisture for 
six weeks. At the end of that time the soils were leached and in- 
creases were found in parts per million of 19.4, 26.0, and 34.1, re- 
spectively, for the blank, CaO, and CaS0 4 treatments. On cutting 
down the time of contact to 24 hours, no increase in soluble potash 
could be found, except from the gypsum treatment. 

Morse and Curry (14) found that upon shaking orthoclase with 
solutions of Ca(OH) 2 , a liberation of potash occurred, which was 
readily fixed when in contact with clay or kaolin. They further con- 
clude, from field studies, that lime was of little benefit in releasing 
potash for the hay crop. 

Fraps (5), from pot studies with applications of CaCO s and 
CaS0 4 , finds no appreciable liberation of potash from either treat- 
ment, as measured by N/5 acid, or the amounts taken up by the crop. 

Briggs and Breazeale (2) found that Ca(OH) 2 had no effect in 
liberating potash from orthoclase or orthoclase-bearing rock. Gyp- 
sum also reduced the solubility of the potash from orthoclase. These 
investigations went a step further, and found no absorption of potash 
by wheat seedlings grown in contact with this particular feldspar and 
additions of lime. 

Plummer (17) grew two crops of nonleguminous plants, oats and 
rye, and two crops of legumes, soybeans and cowpeas, in pots out of 
doors, in a soil very deficient in native potash. This potash supply 
was augmented' by additions of orthoclase, microdine, biotite and 



164 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

muscovite, which represent the potash-bearing minerals of many of 
the soils of the States bordering the Atlantic Ocean. Calcium car- 
bonate was added at the rates of 2 and 4 tons per acre. Determina- 
tions of potash removed by the crop were made in all cases. There 
was no evidence to show that potash had been forced into solution by 
the lime treatment when the nonlegumes were grown. The total 
amount of potash removed by the legume crops was greater when 
the carbonate had been applied, but this should not be taken to mean 
that the available potash had been increased. The lime had evidently 
made stronger plants which were capable of extracting more potash 
than those from the unlimed treatment. 

Where these four potash-bearing minerals were treated with 
Ca(HCO G ) 2 for 96 hours, the solution filtered, and potash deter- 
mined, no evidence of potash replacement could be detected. After 
the last crop, soybeans, had been harvested, the potash dissolved in 
X 5 HXO3 was determined, with no evidence of potash replacement 
from additions of the carbonate. 

The foregoing review represents laboratory and pot work. While 
this is the first step in any line of soil investigation, conditions do not 
always represent those of the field. 

LYSIMETER AND FIELD STUDIFS. 

Lyon and Hizzell ( 10) have reported results of the first 5-year 
period in their lysimeter experiments. They say in part, " so far as 
could be ascertained from the potassium in the drainage water and 
the crop raised on the soil treated with lime and the soil not so 
treated, there was no liberation of the lime treatment." 

Maclntire | 12) has recently reported results of elaborate lysimeter 
studies with limestone, dolomite, magnesite, CaCO :5 , MgCO :1 , CaO, 
and MgO Oil two soil types, and concludes as follows: "With refer- 
encc to these two types of soil, under the prevailing climatic condi- 
tion-. . . . practical and economical applications of burnt calcareous 
limestone, burnt dolomitic limestone, ground calcareous limestone or 
ground dolomitic limestone will not effect a direct chemical libera- 
tion of native soil potassium." 

Turning our attention to actual field conditions we find that water 
cxtractioi of the Pennsylvania plats, as reported by Brown and 
Maclntire (3)1 ihow more potassium in solution from the unlimed 
plat than from that which received the lime treatment. 

W heeler and In associates ( 20 ) concluded that a study of the 
soils of Rhode Island doc<- not indicate that lime should be considered 

•'»s a vigorous potash liberant. 



plummer: effects of liming. 



165 



Effects of Liming on Soil Phosphorus. 

Studies on the effects of calcium and magnesium salts, especially 
the carbonates, on the availability of soil phosphorus do not seem 
to have reached such a state of definiteness as have those on soil 
potassium. 

POT AND LABORATORY EXPERIMENTS. 

The following review of published work on this subject clearly 
indicates that more should be done before we can say that the prac- 
tice of liming the land decreases the need of soils for applied phos- 
phates. 

Kellner et al. (9) in 1890 probably carried on the most compre- 
hensive pot and laboratory experiments on this question up to that 
time. They used bottles to which had been added two soils. One of 
the soils came from a boggy field, high in humus, and the other was 
a subsoil from dry land. Quicklime was added in amounts from 0.25 
to 5 percent of the soil and kept damp for two weeks, after which 
0.05 percent of P 2 O g as KH 2 P0 4 was mixed in and allowed to stand 
for periods of one' and two weeks. The amount of phosphoric acid 
soluble in neutral ammonium citrate was then determined. They 
found that the lime treatment proved very beneficial in increasing the 
availability or reduced fixation of the applied phosphate in the case 
of the high humus soil, but not in the case of the subsoil. 

The two soils were of the same geologic formation, and differed 
only in organic matter. The authors concluded that this constituent 
played an important role. They say, however, that an application of 
lime ahead of one of superphosphates will in all probability have a 
good effect on the crop, especially if the soil is heavily charged with 
iron and aluminum oxids. 

Very probably the lime had its greatest effect in bringing about 
bacterial decomposition of the humus and increasing the solubility of 
its phosphates rather than by actually increasing the solubility of any 
of the applied phosphates. 

Guthrie and Cohen (8) report results of phosphate solubility ex- 
periments, using water and 1 percent citric acid as solvents. A gar- 
den soil, a stiff heavy clay, and a light sandy soil to which had been 
added 1 percent of freshly slaked lime were used. The lime was 
allowed to act for one month. The water-soluble P 2 5 decreased 
during the experiment in all of the soils. Digestion with citric acid 
showed very little alteration in the amounts of soluble constituents 
during this experiment. 

Ellett and Hill (4) have probably carried out the most elaborate 



1 66 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



laboratory experiment on this subject reported up to this time. A 
number of Virginia soils containing high and low amounts were 
used. From their percolation experiments with soil, they conclude 
that phosphate fixation is greater on soils which contain greater quan- 
tities of iron and aluminum compounds. 

The fixation of P l .O- in monoealcium phosphate and acid phos- 
phate by CaCO s , Mg€0 3J FeCO, Fe 2 :; , Fe(OH) 3 , and Al(OH), 
is given in this report. It was observed in these experiments where 
monoealcium phosphate was used, that all the other added materials 
removed from solution a great deal more P 2 5 than did the CaC0 3 . 
On the other hand, where acid phosphate was used, almost as much 
fixation occurred from CaCO ; . as from Fe 2 3 , the most extensive 
absorbing agent used. Gerlach and Ullman claim that P 2 5 removed 
in this manner is available to growing plants. 

Ellett and Hill are of the opinion that the fixation of P 2 5 takes 
place in the surface 6 inches of soil and that evaporation plays an im- 
portant part in this process. They allowed equal evaporation, where 
constant amounts of soluble phosphoric acid were permitted contact 
with known amounts of the same basic materials, and determined the 
subsequent solubility of P 2 5 in neutral ammonium citrate, N/5 hy- 
drochloric acid, and 1 percent citric acid. The hydroxids of iron and 
aluminum locked up from 60 to 70 times as much of soluble phos- 
phates as that fixed by the soil. When CaC0 3 was mixed with these 
hydroxids. the fixation was materially reduced. When CaCO ;! and 
MgCO n were used alone as fixing agents, the resulting compounds 
were almost completely dissolved and would have to be classed as 
available. 

Vegetative experiments are also reported in this paper. Wheat, 
OatS, and corn were utilized as indicators of fixation. The insoluble 
compounds funned from the union of acid phosphate with CaC0 3 , 
I'e(Oll) ., and All Oil)., were compared with acid phosphate and 
ground rock pho-phatc, in pots containing acid-washed sand. The 
yields of dry matter indicate that the basic phosphates, formed by the 
iron and aluminum compound-, are practically equal to acid phos- 
phate p»r oats and coin, and they further show a high degree of 
availability to wheat. 

The conclusions drawn from this work are that the solvents used 
by chemist* to determine availability of phosphoric acid, when ap- 
plied to compounds of fixation or reversion of phosphates by iron 
and aluminum compounds, do not represent in any way their true 
availability and can not be correlated with what the plant can or can 
not assimilate. 



plummer: effects of liming. 



167 



These experiments were continued in the field with no increase in 
available P 2 O according to the N/5 HNO s method. However, in- 
crease in crop yields was obtained by liming, indicating a possible in- 
crease in available P 2 5 not recorded by the solvent, or the beneficial 
effect of a better physical and biological condition within the soil. 

From the growth of a large number of different crops, in sand 
cultures, and using eight different phosphates, Truog (19) has found 
that species of plants differ largely in their ability to extract phos- 
phorus from different sources. A number of species, such as oats 
and corn, are able to utilize the P 2 3 from aluminum and iron phos- 
phates almost to the same extent as that from acid phosphate. How- 
ever, it appeared that alfalfa and the lime-loving plants could more 
readily utilize the phosphorus from precipitated tricalcium phosphate. 
Truog's explanation of this is based on the assumption of an hydro- 
lysis of the precipitated metallic phosphate, which undoubtedly brings 
into solution much of the insoluble P 2 5 and is reflected in increased 
crop growth. Whether additions of lime will break up the combina- 
tions supposed to be formed from the union of the hydrolysed basic 
phosphate and acid organic matter, or acid silicates, has not been 
definitely proved. 

Fraps (6) conducted pot experiments with five soils, to which he 
applied acid phosphate both with and without carbonate of lime. 
Corn and sorghum were used to indicate the effects of treatments. 
The results of this work gave no indication that the addition of lime 
increased the availability of the P 2 5 of acid phosphate. 

FIELD EXPERIMENTS. 

The foregoing results were obtained mainly from laboratory and 
pot tests. Some important data have been secured in the field and 
these will be discussed briefly. 

Wheeler and his associates (21) have conducted extensive field 
experiments upon the effect produced by nine different phosphates 
upon a great variety of crops. The carriers of phosphoric acid in- 
clude acid phosphate, bone meal, phosphate rock, and redondite 
(aluminum phosphate). One series of plats received lime and one 
series received none of this amendment. The experiments were con- 
tinued for a number of years and demonstrated marked differences 
in the extent to which these phosphates were utilized by the different 
varieties of plants. These workers concluded that, instead of prov- 
ing injurious in connection with the soluble phosphates, liming proved 
very helpful in a majority of cases, even in the case of plants not par- 



1 68 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



ticularly in need of lime. The results seem to indicate that liming 
may extend the period of efficiency of the soluble phosphate in the 
case of a soil deficient in or devoid of CaCO s but well supplied with 
the oxids of iron and aluminum. The addition of lime exerted a de- 
pressing effect on the insoluble calcium phosphates. This indicates 
that, on soil well "supplied with calcareous material, the employment 
of more lime might readily prove injurious, thru a depression in the 
availability of phosphorus. 

According to Truog, Ellett and Hill, and others, the precipitated 
iron and aluminum phosphates show a greater degree of availability 
than does the freshly precipitated calcium phosphate, for a time at 
least, in the case of a number of species of plants. This indicates that 
some factor other than that introduced by the addition of lime plays 
an important part in effecting the availability of phosphorus. 

Mooers (14) presents field results from four soil types over a 
period of five years. Cowpeas and wheat were grown on fortieth- 
acre plats, half of each plat receiving lime at the rate of 1 ton to CaO 
per acre. The phosphatic carriers were acid phosphate and finely 
ground phosphate rock. The results show that lime increased the 
efficiency of acid phosphate, but depressed that of the ground rock. 

Effect op Liming on the Availability and Conservation of Soil Sulfur. 

The data on the effects of liming on the availability of soil sulfur 
are very meager. 

The results secured by Lyon and Bizzell (11) with the Cornell 
lysimeters and those of Maclntire (13) are the only available impor- 
tant pieces of work on this subject. 

Lyon and Bizzell report the content of drainage from ten lysimeter 
tanks. Lime, as CaO, was added to five of these tanks at the rate of 
3,000 pounds per acre. Crops were planted on four unlimcd and four 
Iiii ' - ! tank>. Potassium sulfate was added annually at the rate of 200 
pouiuL per annum. < )ne each of the limed and unlimed tanks was 
kepi hare of regetation thruoul the experiment, which ran for four 

years. The uncropped and limed tank yielded an annual increase of 
<, pounds of sulfur in the drainage water as compared with the un- 
limed tank. W here the crops were grown the limed soil yielded about 
" pounds more of sulfur than the unlimed land. The sulfate tanks 
ielded an animal outgo of 5.5 pounds of sulfur more than that from 
tin tank where n<» lime was applied. These data bring out very 
dearly the increase in sulfur outgo, where lime has been added. 

Maclntire I ;i been kind enough to loan the writer tables of unpub- 



plummer: effects of liming. 



lished data which he ha? secured from the lysimeters at the Tennessee 
Agricultural Experiment Station. In one set of 22 tanks Maclntire 
applied ferrous sulfate, iron pyrites, and flowers of sulfur with and 
without lime and magnesia in both light and heavy amounts. He has 
data also relative to the outgo of native soil sulfur as induced by CaO, 
MgO, CaCO~, and MgCO SJ limestone, dolomite, and magnesite in 
amounts equivalent to 8, 32, and 100 tons of CaO per acre. One set 
of 23 lysimeters contained only the surface soil, while another set of 
23 had 1 foot of clay subsoil underlying the surface soil. The ex- 
periments have been under way since July, 191 4. Sulfates are deter- 
mined in the drainage water at the end of each annual period. The 
results show that all the treatments increase the outgo of sulfates in 
the series receiving the 8-ton applications of burnt lime, as compared 
to the no-treatment tanks. The 32-ton and 100-ton treatments of 
CaO practically inhibit the outward movement of sulfur. No such 
retardation of sulfur outgo was caused by the carbonate of lime 
treatments. Magnesium oxid has produced the opposite effect of 
that caused by the quicklime. Xo diminution of sulfate leachings ap- 
pears as a result of any of the heavy additions except in the case of 
burnt lime. All applications of the natural carbonates, when com- 
pared to tanks receiving no carbonate, caused an increased sulfate 
concentration of the leachings. The continued loss of sulfates in 
amounts approximating those which have transpired would effect a 
speedy depletion of the initial organic sulfur content, particularly 
from the magnesium oxid and carbonate treatments. 

Summary. 

This discussion has dealt with the important work touching the 
effects of liming on the availability of soil potassium, phosphate, and 
sulfur. 

The more recent research, embodying laboratory extractions with 
weak solvents, pot studies using a variety of plants as indicators of 
the concentration of the soil solution in potassium and the analyses of 
their ash, lysimeter experiments from which the outgo of potassium 
has been measured, and field tests, have failed to show that basic 
compounds of calcium and magnesium increase, by chemical action, 
to any practical extent, the availability of the soil store of native 
potassium. 

More research needs to be carried out before we can say that addi- 
tions of lime will reduce the necessity of applying soluble phosphates 
to the soil. As measured by yields, phosphates of iron and aluminum 



IJO JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



seem to be as available as calcium phosphates. It is very probably 
true that fixation of phosphatic fertilizers by colloidal absorption in- 
duced by iron and aluminum oxids is responsible for the failure of 
some crops to respond to phosphorus additions. Additions of lime 
on such soils undoubtedly flocculate some of these colloids, which 
gives the soil a better physical condition for plant growth. 

Additions of lime, before or after applications of soluble phos- 
phates, have greatly increased the efficiency of the phosphatic fer- 
tilizer. When insoluble calcium phosphate has been applied, it seems 
that applications of lime have reduced the effectiveness of the phos- 
phate in a majority of cases. 

The scant data of lysimeter experiments only, which deal with the 
question of sulfate availability or conservation, seem to show that 
liming, with small amounts of CaO, both small and large amounts of 
MgO, MgC0 3 , limestone, dolomite, and magnesite, increases the solu- 
bility of native soil sulfate. Heavy applications of CaO, for a few 
years at least, apparently reduce this loss of sulfur from the soil. 

LITERATURE CITED. 

1. Bradley, C. E. The reaction of lime and gypsum on some Oregon soils. 

In Tour. Indus. Eng. Chem., v. 2, no. 12, p. 529-530. 1010. 

2. Briggs, L. J., and Breazeale, J. F. Availability of potash in certain ortho- 

clase-bearing soils as affected by lime or gypsum. In Jour. Agr. Re- 
search, v. 8. no. 1, p. 21-28. 1917. 

3. Brown, B. E., and MacIntire, W. H. The relation of certain water-soluble 

soil constituents in plats 16-24. In Ann. Rpt. Pa. State Col. 1910-1911, 
p. 105. 1912. 

4. Eli. 1 rr, W. B., and HlLL, H. H. Contribution to the study of phosphoric 

acid in soils and fertilizers. In Va. Agr. Expt. Sta. Rpt. 1909-1910, p. 
44-65. iQi 1. 

5. Fraps, G. S. The effect of additions on the availability of soil potash, and 

the preparation of sugar humus. Texas Agr. Expt. Sta. Bui. 190. 1916. 

6. . Effects of lime and carbonate of lime on acid phosphate. Texas 

Agr. Expt. Sta. Bui. 223. 1917. 

7 Gi BB, K. \Y. The effect of lime upon the solubility of soil constituents. 
In Jour. Indus. Engin ( hem., v. 2, no. 7, p. 315, 316. 1910. 

R rnkiK, V. I'... and Cohen, L. Note <»n the effect of lime upon the avail- 
ability of the soil constituents, hi Agr. Gaz. N. S. Wales, v. 18, no. 12, 
p 952 056. 1907. 

o. K11.1. m.k. ()., 11 ,\ i.. Researches on the action of lime as a manure, with 
-p" i ll regard to paddy fields. In Col. Agr. Tokyo Bui. 9, p. 1-25. 1891. 
Hi Lyon, T. L. ;md P.1//11 1., J. A. Calcium, magnesium, potassium, and 
'1mm in the drainage water from limed and unlimed soil. In Jour. 
Amcr. Sor. Agroii., v. 8, no. 2, p. 81 87. 1016. 

II. . The loss ,,f sulfur in drainage water. In Jour. Amer. Soc. Agron., 

v. 8, no. 2, p. 88. n>i6. 



plummer: effects of liming. 171 

12. MacIxtire, W. H. The liberation of native soil potassium induced by 

different calcic and magnesic materials, as measured by lysimeter leach- 
ings. In Soil Science, v. 8, no. 5, p. 337-394. 1919. 

13. , Willis, L. G., and Holding, W. A. The divergent effects of lime and 

magnesia upon the conservation of soil sulfur. In Soil Science, v. 4, 
p. 231-235, 191/. 

14. Mooers, C. A. Fertility experiments in a rotation of cowpeas and wheat. 

Tenn. Agr. Expt. Sta. Bui. 90. 1910. 

15. Morse, Fred W., and Currv, B. E. The availability of the soil potash in 

clay and clay loam soils. N. H. Agr. Expt. Sta. Bui. 142, p. 49. 1909. 

16. Parker, E. G. Selective adsorption by soils. In Jour. Agr. Research, v. 1, 

no. 3. P- 179-188. 1913- 

17. Plummer, J. K. Availability of potash in some common soil-forming 

minerals. Effect of lime upon potash absorption by different crops. /* 
Jour. Agr. Research, v. 14, no. 8, p. 297-315. 1918. 

18. Storer, F. H. Agriculture in some of its relations with chemistry, v. 1, p. 

207. Scribner's, New York. 1888. 

19. Truog, E. The utilization of phosphates by agricultural crops, including 

a new theory regarding the feeding power of plants. Wis. Agr. Expt. 
Sta. Research Bui. 41. 1916. 

20. Wheeler, H. J. Studies of the needs of Rhode Island soils. R. I. Agr. 

Expt. Sta. Bui. 139, p. 75. 1910. 

21. and Adams, G. E. A comparison of nine different phosphates, upon 

limed and unlimed land, with several varieties of plants. R. I. Agr. 
Expt. Sta. Bui. 114. 1906. 



THE FINENESS OF LIME AND LIMESTONE APPLICATION AS 
RELATED TO CROP PRODUCTION. 1 

William Freak. 2 

This subject, which, by the courtesy of your program committee 
for this meeting, I have been asked to discuss before you, had not, 
until about a decade ago, been a matter of at all rigorous investiga- 
tion, altho such observations and experiments as were then available 
had led to very generally adopted recommendations for the use of 
care to secure a fine product in the slaking of lime and to choose 
fine-grained rather than the coarser marls for soil dressing, where 
such choice was possible. 

When machinery had been developed by use of which limestone 

1 Contribution from the Pennsylvania Agricultural Experiment Station, State 
College, Pa. Presented at the thirteenth annual meeting of the American 
Society of Agronomy, Springfield, Mass. October 19, 1920. 

2 Vice director and experimental agricultural chemist, Pennsylvania Agricul- 
tural Experiment Station. 



IJ2 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



could be well pulverized, and when the need thruout the humid re- 
gions of the world for the establishing of the liming practice as an 
essential to the most economical crop production and to the mainte- 
nance of soil productiveness had been recognized, as well as the fitness 
of ground limestone as a substitute for the oxid or the hydrate of 
calcium, the question of the requisite fineness of these materials 
assumed economic importance. 

ELEMENTS OF ECONOMIC IMPORTANCE. 

This importance is due chiefly to the multiplier rather than to the 
multiplicand of production; not to one main gain from a single appli- 
cation, but to the tremendous values involved in the use of millions 
of tons of material upon millions of acres of land, over and over thru 
the years, and the influence of these values upon national and world 
prosperity. 

ASPECTS OF THE LIMING ACTION. 

Let us pause for a moment to consider the main elements of the 
liming reaction. Altho the physical system involved is in reality 
highly complex, we may regard the primary interchange as one be- 
tween two solids, lime or limestone and an acid soil, and a liquid, the 
soil moisture. All experiments upon methods by which the lime re- 
quirement of an acid soil are sought to be determined show that in 
the presence of a solution of the full amount of calcium hydrate or 
calcium bicarbonate in abundance of water intimately mixed with the 
soil, neutralization of the latter, or, if you prefer, satisfaction of its 
lime-absorption capacity is, except for a small percentage of the 
whole, almost immediately accomplished. In other words, the affinity 
is strong between the alkaline calcium solution and the acid soil. 

On the other hand, the rate at which water can dissolve calcium 
hydrate, and especially the calcium carbonate, is slow. In other 
words, the affinity here is relatively weak; furthermore, the quantity 
of these two substances required to form a saturated water solution 
Is small, as compared with the amounts of many other substances 
water can dissolve. Silt y loam soil may average about 18 percent 
of moisture thru the growing season. This represents roughly 400,- 

000 pounds of water to 2,000,000 pounds of air-dry soil — an acre- 
ht to plow depth. This amotinl of water, when fully saturated 

at 60 to 70' F. could hold 6.800 pounds of calcium hydrate, but only 

1 little more than 5 pounds of the carbonate. H the water were 
saturated with carbon dioxid. the calcium, whether originally pre- 
sented as o id, hydrate, or carbonate, is assumed to take the bicarbo- 



frear: fixexess of limestoxe. 



173 



nate form and, under the conditions named, the saturated soil solution 
would carry the equivalent of about 500 pounds of calcium carbonate. 
All these figures are based upon the assumption that the dissolved 
solids can be uniformly distributed thru the soil moisture. In brief, 
soil water can give up its lime to the soil much more rapidly than it 
can take its supply from the applied lime or limestone. 

FINENESS OF LIMESTONE AS IT AFFECTS SOLUTION RATE. ' 

The time required to dissolve a given mass of any solid substance 
capable of solution in a given liquid is, as you well know, dependent 
for one thing upon the amount of the surface it exposes to the liquid ; 
the greater the surface, the more rapid the solution up to the limit of 
saturation. As the subdivision of the mass is carried forward, the 
aggregate surface presented by its separated particles increases in 
proportion as their diameter decreases. That this general rule holds 
good for ground limestone has been shown by White (15), Christen- 
sen (7), and Broughton (6) and his associates. It is doubtless 
equally true of the oxid and hydrate forms. The finer the subdi- 
vision, therefore, the shorter the time the soil moisture will require 
to dissolve a definite part of the applied material. 

LIMESTONE POROSITY. 

At this point I venture to interject a qualifying detail: Some years 
ago, I suggested (9, p. 175) that the porosity of the limestone would 
affect the amounts of surface presented by equal masses of stones 
equally finely subdivided, and that this difference would somewhat 
alter the respective rates of solution. The contrast in porosity pre- 
sented by dense marble and by coral rock are well known to all who 
have observed these materials. What volume of pore space charac- 
terizes limestone has, however, been the subject of little study. Dr. 
George Otis Smith, Director of the U. S. Geological Survey, in a 
letter to the writer, states that the percentages of water absorption 
represent from 15 percent of pore space in porous rock down to negli- 
gible quantities in such marbles as those of Vermont, Georgia, and 
Tennessee. Bleininger and Emley (5), -in determinations upon rocks 
used in studying lime-burning, found volumes of pore space ranging 
from about 7.5 percent down to less than 1 percent, with the lower 
figures far the more frequent. Unpublished data secured by Walter 
Thomas, working under the writer's direction to determine the por- 
osity of stones representing the chief limestone formations from 
which Pennsylvania's commercial ground limestones are obtained, 



174 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



show from 0.4 to 4.7 percent of pore space. The corresponding pore 
surface is unknown. The pore diameters doubtless differ greatly. 
"Whatever surfaces they represent, for reasons which must be readily 
apparent the solution efficiency of these internal surfaces must be 
much below that of an equal external surface. 

FINENESS AS IT AFFECTS DISTRIBUTION. 

Finer subdivision not only increases the proportion of surface to 
mass, but also lends itself to more perfect mixing with the soil. A 
slowly soluble solid will dissolve more rapidly if kept in suspension 
in the solvent than if exposed to a thick layer at the bottom of a 
quiet body of the solvent. The stirring greatly expedites the homo- 
geneous distribution of the solute, whereas, unaided diffusion works 
slowly. The study of diffusion in soils shows that, when the soils 
are in their ordinary field condition, the dispersion of soluble mate- 
rials by this process is extremely slow and also very limited in extent 
(9. p. 68). For this reason, it is very important to the prompt and 
efficient use of lime applications, that they be intimately mixed with 
and uniformly distributed thru the soil masses upon which they are 
to act. 

POT EXPERIMENTS UPON EFFECTS OF LIMESTONE FINENESS ON CROP YIELDS. 

Whether the ascertained more rapid rate of solution of fine vs. 
coarse limestone particles is, after all, of sufficient influence to affect 
crop yields can probably best be determined by pot experiments with 
soils of distinctly high lime requirement and with crops of high sus- 
ceptibility to lime treatment. American experiments of this kind are 
those of W. Thomas (13) working under the writer's direction, of 
J. W. White (15), and of Nicholas Kopeloff (10). Those of Thomas 
and Frear and of White were made on the same highly acid, silty 
clay loam soil; those of Kopeloff upon four acid soils from widely 
Separated localities, .and of sandy loam and silty loam textures. 
Thomas and I rear cropped with medium red clover, Kopeloff with 
crimson clover, and White with nine different crops in succession, 

lome of these very susceptible to lime influence, two relatively indif- 

h-rent. I 1m duration of Kopeloff s cropping was not stated; that of 
1 lionia- and frear was X.5 months; that of White, nearly three years. 
The BneneSfl of limestone represented in Kopeloffs work ranged 

from that which passed a 20-mesh btU not a 40-mesh sieve to that 

which passed a j<*)-n\v*h ; in Thomas and f rear's work, the lower 
limil Wai the same as in Kopeloff s study, but the material that passed 



frear: fineness of limestone. 175 

a 100-mesh sieve was not graded ; while, in White's work, the coarsest 
material passed an 8-mesh but not a 12-mesh sieve, and the finest 
passed a 100-mesh sieve. That is, as to range of fineness, these pot 
tests included probably the finest material open to practical use, but 
not the coarsest. The crop yields, taking the highest from a lime- 
stone treatment as 100, as they appeared for the single crops from the 
first two of these experiments, were : 



Table i. — Relative crop yields from soil limed with limestone of varying fineness. 





Thomas and 


Kopeloff. 


Material used in liming. 










Frear. 


Norfolk sandy 


Wooster silt 


Carrington 


Cumberland 






loam. 


loam. 


silt loam. 


silt loam. 


Check 





70 


24 


70 


38 


Limestone : 












20-40 mesh 


12 


80 


88 


90 


50 


40-60 mesh 


58 










60-80 mesh 


76 


95 


89 


87 


93 


80-100 mesh 












100-200 mesh 


{100} 


92 


IOO 


92 


95 


200+ mesh 




100 


96 


IOO 


100 


Lime 




no 


95 


108 


80 



Grouping the results obtained by White by years rather than using the 
data separately for single crops, and taking as 100 the increases over 
checks obtained by 100-mesh limestone, we have the data shown in 
Table 2 : 



Table 2. — Increases over checks obtained from the use of limestone of varying 
degrees of fineness, the increase over check obtained from the use of 
100-mesh limestone being taken as 100. 



Material used in liming. 


First year, red clover, 
Canada field peas, 
sweet clover. 


Second year, wheat, 
soybeans, hairy vetch. 


Third year, crimson 
clover, Hungarian 
millet, lettuce. 


Limestone: 








8-12 mesh 


13 


5 


9 


20—40 mesh 


20 


32 


36 


60-80 mesh 


6l 


65 


87 


100 mesh 


IOO 


IOO 


100 


CaO 


III 


125 


no 



The data from the three experiments show a general tendency for 
the first yields after application to be superior for burnt lime as com- 
pared with limestone fine enough to pass a 100-mesh sieve, and for 
the yield to increase in a general way with the higher fineness of the 
limestone used. The limestone used by Kopeloff in a fineness of 
20-40 mesh was, however, much more influential upon production 



I "6 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



than that of the same diameter used by the others named. In White's 
pot experiments the 8-12 mesh stone had a slight effect- in each of 
three years. It deserves note that, owing to the more perfect mixing 
than is usually obtainable for field applications, to the maintenance of 
optimum moisture, and to exposure to greenhouse temperatures dur- 
ing the winter months, the potted soils were undoubtedly more active 
during the periods of the respective tests than are field soils. In 
other words, the effects were doubtless produced in the pots in much 
less time than would be required to obtain these effects under field 
conditions. In the third year of White's experiment it is worth 
noting that, despite the use of different species of crop plants during 
the several years of the test, the order of yield in relation to fineness 
of the limestone was practically unchanged from that of the first year. 
The substantial gains from the use of 100-mesh over 8-mesh for the 
several crops grown by White are shown by the following ratios in 
which the yield of air-dry weight (green weight in the case of let- 
tuce) with 8-mesh is stated as 1, the second figure of each ratio being 
the proportional yield with 100-mesh stone : 



Red clover 1:3 

Canada field peas 1 : 1.7 

Sweet clover 1:2.6 

Wheat 1 : 1.2 

Soybeans 1 : 2.0 



Hairy vetch 1:2.7 

Crimson clover 1 : 1.5 

Hungarian millet 1: 1.1 

Lettuce 1 : 8.0 



In White's, as in Kopeloff's, studies, crimson clover shows 70 per- 
cent as high a yield with 20-mesh stone as with 100-mesh; that is, the 
more favorable standing shown for the coarser grade may be charac- 
teristic of some plant species, but not of others. 

FIELD EXPERIMENTS ON INFLUENCE OF FINENESS UPON CROP YIELDS. 

Field experiments in which limestone of definite grade as to fine- 
ness has been applied are few in number. Ames and Schollenberger 
d) report some interesting studies upon a soil distinctly acid (re- 
quirement, 5.750 lbs. carbonate by vacuum method). The crop re- 
sult s obtained up to the time of the report are stated proportionally 
to that given by nonmagnesian limestone passing an 80-mesh sieve 
r Table 3). 

The crop differences up to that time are clearly not decisive. 
Thome (14) relates the crop results of applications of coarse 

* reenings (all passing £4-in, mesh >,of a finer, highly calcareous stone 
(all passing a J4o-in. mesh; 35 to 45 percent, of a H,o<r m ' meshf) 

and of a hydrated lime. Of these dressings (made in addition to a 



FREAR : FINENESS OF LIMESTONE. 



177 



Table 3.— Crop results obtained from the use of limestone of varying fineness, 
those from limestone of less than 1/80 inch diameter taken as 100. 



Material used in liming. 


Soybean hay. 




Wheat (grain and 
straw). 


Clover hay. 




106 


114 


97 


Limestone: 










IOO 


IOO 


IOO 




102 


98 


• 91 


1/8 to 1/20 


99 


104 


86 


i/3 to 1/8 


97 


96 


100 




109 


101 


86 


Check 




92 


73 



a Mechanical composition, percent: coarser than ^-mesh, 5; % to % 37; 1 /s 
to %0, 27; ^0 to 1 so. 19; finer than %o, 12. 

"basic dressing" of farm manure and acid phosphate), those of the 
limestones were in contrasted amounts of 2 and 4 tons each ; the hy- 
date, 1.5 tons. The money values of crop increases, cost of liming, 
and net value of increases from corn, oats, wheat, and red clover hay 
in the course of a single rotation are stated in Table 4. 



Table 4. — Value of crop increases obtained from the use of various forms 

of lime. 



Material used in liming. 


Total value of 
crop increase. 


Cost of liming. 


Net value of in- 
crease. 


Screenings, 2 tons 


515.78 


$7-50 


$8.28 


Screenings, 4 tons 


23.60 


15.00 


8.60 


Fine stone, 2 tons \ 


24.16 


12.00 


I2.I6 


Fine stone, 4 tons | 


33-38 


24.00 


9-38 


Hvdrated lime, 1.5 tons 


28.52 


16.50 


12.02 



The lime requirement of the soil at the time of the liming is not 
stated. The superior crop yields from the finer material stand clearly 
forth. 

Barker and Collison (3), judging from analogy with ground bone, 
comparisons between hvdrated lime and limestone of rather indefi- 
nitely ascertained fineness, and the stand of alfalfa on various fields, 
reached the safe conclusion that if enongh 10-mesh limestone (includ- 
ing all associated fine material) is used to last for three years it will, 
without question, give fully as good results the first year as a some- 
what smaller amount of extremely fine material. 

Various other studies, more general in character than those above 
mentioned, have led to expressions of judgment in favor of the pro- 
ductive effects of limestone of superior fineness of subdivision, but I 
will not give detailed attention to them in this connection. 



1 78 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



FINENESS OF LIMESTONE AS IT AFFECTS SOIL CONDITIONS. 

Certain related studies of soil condition following liming have been 
made by White, Kopeloff, and Ames and Schollenberger in connection 
with the crop production results already given. These relate to the 
rate of decomposition of the applied carbonate, the degree of acidity 
correction, and, in several instances, to the correlated activity of soil 
organisms. 

W hite found at the end of his 3-year pot tests that of the carbonate 
dressings initially applied, there remained in carbonate combination, 
of the 8-mesh stone, 85 percent ; of the 20-mesh, 57 percent ; of the 
60-mesh, 19 percent ; and of the 100-mesh, 8 percent. 

Ames and Schollenberger found residual as carbonates after 16 to 
23 months in the field soils to which nonmagnesian stone had been 
applied in different degrees of fineness : Of that which passed an 
80-mesh sieve, 58 percent ; 20- to 80-mesh, 48 percent ; 8- to 20-mesh, 
77 percent; 3- to 8-mesh, 84 percent; coarse screenings, 103 percent. 

Stewart and YVyatt (12), in a comparison which included both 
magnesian and nonmagnesian stone applied in various combinations 
and in degrees of fineness severally expressed in the rather indefinite 
terms " % inch down," " % to % () inch," " % i ncn down," and 
"% ^ch down." found a larger proportion of carbonates residual 
from the group " % to Mo inch " than from the others, and least from 
the group " M><> inch down." These relations were found true alike 
where light, medium and heavy applications (severally at the rate of 
500, 1,000, and 2,000 pounds a year) of the respective groups as to 
fineness were compared. The experiment had run for four years, 
with two applications to each plat during that time. It is much to be 
wished that in the continuance of their work, these investigators may 
make such mechanical analyses as will enable us to compare more 
closely as to fineness the different limestones used. 

Related studies were made also as to the correction of acidity ef- 
fected by the respective limestone applications. White found the 
correction by burned lime and 100-mesh stone complete at the end of 
Hi'- firsi year; by <V>-mcsh stone, seven-eighths complete at the end of 
the first year and entirely complete the next year; by 20-mesh stone, 
one-half, five-sixths, and entirely at the end of the first, second, and 
third years, respectively; and by <s mesh stone, one-seventh at the end 
of the first year and onl) two-sevenths al the end of the third year. 
Where the finest stone was used, acidity bad reappeared in slight 

decree at the end of the third year. 

Kopeloff found j Veitch method I at the end of his study, the acid- 



FREAR I FINENESS OF LIMESTONE. 



179 



ity had decreased four-fifths with stone finer than 100-mesh; two- 
thirds with 60- to 80-mesh ; and one-third with 20- to 40-mesh. 

Stewart and Wyatt, using the Hopkins method for acidity, found in 
the case of several applications of limestone, no characteristic differ- 
ence in acidity correction between the several fineness grades, whether 
with light, medium, or heavy applications ; tho the acidity decrease 
was greater in each instance as the amount of limestone applied in- 
creased. This finding of efficiency for the coarse stone must be 
regarded as exceptional. 

The last mentioned investigators attempted to calculate, from the 
amount of carbonate decomposed and of acidity corrected, the amount 
of limestone lost from the soil. But it is not safe to assume that 
calcium, which has parted from its carbon dioxid to assume other 
states of combination in the soil, has wholly lost its acidity corrective 
value in the exchange ; especially should this assumption be avoided 
when the total application considerably exceeds the lime requirement 
at the time of application. 

May I again digress to remark upon the commendation occasion- 
ally appearing in lime literature for " durability " of the stone in the 
soil? Its economic value while ''durable" is equal to that of the 
celebrated " single talent buried in a napkin." Thus durably buried 
it is losing interest at a compound rate. Serviceability, not dura- 
bility, is what is required. Limestone does no work until its decom- 
position occurs. 

OBSERVATIONS FROM NATURE. 

Observation of natural soil and rock formations suggest that coarse 
fragments of calcium carbonate, w r hether amorphous, crystalline, or 
organized in the form of molluscan shells, do not always dissolve rap- 
idly in the earth. Fossils in sandy or shaly rocks frequently show 
replacement of lime by other elements, but not always, even in the 
absence of a surrounding mass of calcareous material. We have in 
Pennsylvania, near the junction between the Chemung and the over- 
lying Catskill formations, a tough rock of characteristic exposure 
known as the Burlington limestone. It carries from 40 to go percent, 
but usually only a little over 60 percent, of calcium carbonate in the 
form of small shells embedded in a clayey matrix. When it is 
burned, the thin white shells stand out distinctly from the deep red of 
the burned matrix. The adjacent rock materials are not distinctly 
calcareous. 

Bernard (4) found, in a highly calcareous soil of the Jurassic re- 
gion of France, deposits of coarse limestone gravel imbedded in clay 



ISO JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



low in lime. Such soils did not, like other soils of like lime richness 
due to fine particles of the carbonate, produce chlorosis of the vine so 
common in that region. De Angelis (2) has recently made a like 
observation. 

Limestones usually break up very slowly to form soil and, at the 
surface of contact with the overlying material, commonly form a 
marly residue, which, in turn, becomes new soil. But Noyes (11) 
has recently noted in a distinctly acid subsoil, adjacent to the under- 
lying limestone from which it was formed, fragments of residual lime- 
stone ranging in size from that of a wheat kernel to others four-fifths 
of an inch in diameter. 



Plats 34, of the General Fertilizer Series of the Pennsylvania Agri- 
cultural Experiment Station, have been biennially dressed, since about 
1 88 1, with limestone at the rate of 4,000 pounds to the acre. Until 
1909, these applications consisted of screenings; since then, of ground 
limestone practically free from particles that were coarser than 60- to 
8omesh. The screenings used in 1908, which probably typified fairly 
the material used in earlier years, carried 24 percent of particles that 
would not pass a 703 sieve, and 55 percent that would not pass a 
50-mesh sieve. In November. 1914, about six and a half years after 
the last coarse application, Walter Thomas, of my laboratory, sam- 
pled at my request the surface soil of the plats Nos. 34 on the four 
tiers of the experimental tract. Samples were taken by means of a 
trowel, at fifteen symmetrically located points on each plat. The 
samples were air-dried, composited, quartered down, screened first 
through a 3-111. m. round-hole sieve, and then through a J / 2 -m.m. sieve. 
These "coarse" and "medium " fractions showed numerous par- 
Nile- of limestone. Determinations of carbon dioxid in this residual 
limestone -Ik. wed 42.4 to 42.5 percent, corresponding to a limestone 
of about 96.5 percent purity. The coarse and medium fractions con- 
tained carbonates equivalent, on the acre 7-inch base, to the following 
amounts : 



Some of the limestone particle- were picked (Hit, washed, and photo- 
graphed. The color wa- the fresh bine of the original Trenton stone 



FATE OF COARSE PARTICLES IN AN ALKALINE SOIL. 



Tier I 



3,869 



Tier II 
Tier II! 
Tier IV 



4405 
6,639 
6,050 



frear: fineness of limestone. 



181 



free from iron stain. The sharpness of angles is obvious in the pho- 
tograph, which is enlarged several diameters to bring out clearly this 
character (fig. 3). 

If, during their stay in the soil, none of the coarse particles were 
translocated to a deeper layer or disrupted by frost, these coarse resi- 
dues represent the applications of not less than four to six years, and 
a duration of stay in the soil of not less than ten to twelve years before 
the sampling. The associated fine soil is, however, highly alkaline 



Fig. 3. Residues, years old, from coarse limestone applications on Plat 34 
of the general fertilizer series, Pennsylvania Agricultural Experiment Sta- 
tion. 



with fine particles of limestone, and more highly protective of the 
coarser particles against solution than would be the environment of 
an acid soil. 

THEORY AS TO LIMING PRACTICE. 

Teachers and investigators have taken two opposite views regard- 
ing the value of coarse limestone. One group emphasizes the impor- 
tance of fineness of particle ; the other advises abundant application 
of material, even tho a considerable proportion of it be quite coarse. 
The theory of the latter group is that with the coarse material there 
is enough " fines " to effect an immediate and rapid crop increase, and 
that, the soil acidity being corrected by these " fines," the later de- 



1 82 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



mands can be well supplied by the more slowly soluble, coarse par- 
ticles. The cost of application is held to be less a unit weight when 
the amount is large, and an equal application of fine material, it is 
urged, would tend to increase lime loss in drainage water. Admit- 
tedly there is some truth in these views ; how much, is the question. 

So long as the fine material makes and keeps the soil moisture satu- 
rated with the carbonate, little can dissolve from the relatively small 
surfaces- of the coarse material. The slow rate of decomposition of 
the larger particles in the presence of an excess of fines has just been 
shown. White's experiments show that particles averaging about 
io-mesh. even when no fines were present, decomposed only one- 
fourth in a highly acid, potted soil intensively cropped for three years, 
doubtless representing twice as long a period under field conditions. 

FINENESS OF AGRICULTURAL LIMESTONE IN CURRENT USE. 

It is now in place to note that the description of the fineness of a 
limestone solely by reference to the finest screen thru which all of 
it will pass is not satisfactorily definite. Different machines and dif- 
ferent stones produce very considerably different powders even tho 
the coarsest components of these powders may have approximately 
the same diameters. This fact is well illustrated by the percentage j 
data secured by the Pennsylvania Department of Agriculture in the 
e xamination of commercial ground limestones during 1916, 1918, and " 
1919, as shown in Table 5. 



Table 5. — Percentage of particles qf various sizes in samples of commercial , 

limestone. 



Year and number of samples. 


Coarser than 
10-mesh. 


IG- to 50-mesh. 


50- to 100-mesh. 


Finer than 
100-mesh. 


Average for all brands: 










1916 (17) 


0.9 


17-5 


II.9 


69.7 


1918 (11) 





13-6 


10.2 


76.2 


1919 (14) 





15-8 


IZ.4 


72.8 


( oarM-r brand- : 










1916 (2) 


2.9 


554 


I2.0 


30.0 


1918 (2) 





50.0 


14-5 


35-5 



I In- coarser brands cost the buyer about as much as those of aver- 
age fineness. 

I bit of nineteen samples, mosl Of them farm-ground, recently anal- 
Eed in my laboratory, two contained over 80 percent of 100-mesh 

material; three, mdre than 50 percent. The percentages of material 

that pa- <d ;i jo mesh but not a 100 mesh sieve were quite low, as a 



FREAR : FINENESS OF LIMESTONE. 



183 



rule. Four contained more than 50 percent coarser than 20-mesh ; 
nine others more than 50 percent that would not pass a 40-mesh. The 
average for the nineteen samples showed 41 percent of material finer 
than 100-mesh; 11 percent. 40- to 100-mesh; 20 percent, 20- to 40- 
mesh ; and 28 percent coarser than 20-mesh. In other words, a so- 
called " 10-mesh " stone may be either rather coarse or predominantly 
fine. Concerning the costs of production of these contrasted mate- 
rials we know too little. 

The problem is economic, and can not be determined without in- 
cluding all the economic factors. The freight, hauling, and applica- 
tion costs are identical for the coarse and fine fractions, if the material 
is delivered in bulk. Fippin (8), proceeding upon the assumption 
that average 8-mesh stone costs at the quarry $2.50 a ton, and the 
50-mesh S3. 50; that the railroad haul is 100 miles and the wagon haul 
5 miles : and finally, that 50-mesh stone is entirely available in five 
years. 20- to 50-mesh half available, and coarser than 20-mesh not at 
all available in that time, figures the relative costs of 100 pounds of 
available oxids in stone of 95 percent purity as Si. 20 for the coarse 
and S0.846 for the finer stone. That is. of course, an approximation. 
Stone coarser than 20-mesh will, sooner or later, become available and 
is not, therefore, without some slight value. If the application of 
the finer fraction of the ground stone is sufficient to bring maximum 
crops, the net return is diminished by the additional investment in the 
coarse stone with added compound interest until the coarse particles 
come into action ; and if they then fail to keep up maximum produc- 
tion — which is very probable — there is a further loss in crop sales and 
compound interest on the sales deficiencies. 

The matter is of enough economic importance to justify much more 
carefully checked field experiments for a number of rotations with 
limestone of carefully ascertained fineness and composition, with a* 
thoro cost method applied to the results. 

Until such results are at hand, it is my conviction, from the facts 
now in hand. that, without carrying the detail to extreme refinement, 
we should duly emphasize the present value of the fine material and 
avoid all suggestion of considerable and early returns from material 
coarser than 40-mesh. and certainly from that coarse^ than 20-mesh. 

Literature Cited. 

1. Ames, J. W., and Schollexberger. C. J. Liming and lime requirement of 

soil. Ohio Agr. Expt. Sta. Bui. 306. 1916. 

2. Axgelis, D'Ossat G. de. In Staz. Sper. Agr. Ital., v. 47, p. 603-620. 1914. 

3. Barker, T. F., and Collisox, R. Ground limestone for acid soils. X. Y. 

State Agr. Expt. Sta. Bui. 400. 1915. 



184 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



4. Bernard, A. Le Calcaire. 1892. 

5. Bleixixger and Emley. The burning temperatures of limestone. In 

Trans. Amer. Ceramic Society, 191 1, p. 618. 191 1. 

6. Broughtox, L. B., Williams, R. C, and Frazer, G. S. Tests of the avail- 

ability of different grades of limestone. Md. Agr. Expt. Sta. Bui. 193, 
p. 34- 1916. 

7. Christexsex. H. R. Experiments on lime and marl. In Tidsskr. Pl'ant- 

eavl., v. 25, p. 377. 1918. Abs. in Expt. Sta. Rec, v. 42- 1920. 

8. Fippix, Elmer O. The use of lime on the farm. Cornell Univ. Reading 

Course for the Farm, Lesson ' 148, p. 77~79- T 9!9- 

9. Frear, Wm. Sour soils and liming. Pa. Dept. Agr. Bui. 261, p. 175. 1915. 

10. Kopeloff, Nicholas. Effect of fineness of subdivision of pulverized lime- 

stone on the yield of crimson clover and the lime requirement of soils. 
In Science, n. s., v. 45, p. 363-365. 191 7. 

11. Xoyes. J. A. In Jour. Assoc. Official Agr. Chem., v. 3, p. 151-153- IW- 

12. Stewart, Robert, and Wyatt, F. A. Limestone action on acid soils. 111. 

Agr. Expt. Sta. Bui. 212, p. 280. 1919. 

13. Thomas, Walter, and Frear, William. Experiments to determine the 

influence of the fineness of subdivision and richness in magnesium car- 
bonate of crushed limestone used for amendment of acid soil's. In Ann. 
Rpt. Pa. State Col. Agr. Expt. Sta., 1912/13, p. 206-219. 1913. Also, in 
Jour. Indus, and Engin. Chem., v. 7, p. 1,041. 1915. 

14. Thorxe, C. E. The maintenance of soil fertility. Ohio Agr. Expt. Sta. 

Bui. 336, p. 607-608. 1919. 

15. Whiite, J. W. The relative value of limestone of different degrees of 

fineness for soil improvement. Pa. Agr. Expt. Sta. Bui. 149, p. 7. 1917. 

Membership Changes. 

The report in the March issue showed a total membership at that 
time of 609. Since that time 27 new members have been added and 
4 lapsed members have been reinstated, while 4 have resigned, mak- 
ing a net gain of 27 and a present total membership of 636. While 
ihc-c gains arc encouraging and occasional library subscriptions are 
being received which help to swell the total fund available for pub- 
lication, many more ne w members must be added if the Journal is 
to continue thruout the year on its present scale. 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. May, 1921. No. 5 



THE COMPARATIVE EFFECTS OF VARIOUS FORMS OF LIME 
ON THE NITROGEN CONTENT OF THE SOIL. 1 

C. A. Mooers and W. H. McIntire. 2 

That liming on acid soil increased ammonification, nitrification, 
and the oxidation of organic matter has been well established for 
some }-ears. However, data showing quantitatively the effect of 
liming over a series of years on either the nitrogen or the humus 
content of the soil are not abundant. Attention is called in the dis- 
cussions which follow to some of the more pertinent information 
on this subject. As to the comparative effects of various forms of 
lime very few data are available. This phase of the subject is of 
much practical importance, especially in view of a rather widespread 
opinion that the application of burnt lime leads to a "burning" or 
undue loss of soil organic matter and that the continued application 
of this material may, in the course of time, lead toward soil barren- 
ness rather than soil fertility. On the other hand, the carbonate 
forms of lime have been assumed to have little or no effect of this 
kind. 

The Experimental Conditions. 

THE SOIL, CONTAINERS, AND PLACEMENT. 

The experiments which furnish the basis of this article were be- 
gun in July, 1913, and cover a 5-year period. Only one kind of soil, 
a fertile Cumberland loam from the University farm at Knoxville, 

1 Presented at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 19, 1920. 

2 The senior author is vice-director and agronomist and the junior author is 
soil chemist of the University of Tennessee Agricultural Experiment Station, 
Knoxville, Tenn. 

i8.s 



186 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



was used. The approximate mechanical composition is given in 
Table i, and the chemical analysis in Table 2. This soil is a friable 
loam, above the average of Tennessee farm land in productiveness 
and well suited to the usual farm and garden crops. The experiments 
were made in galvanized iron rims, 1 foot in depth and 2.225 feet 
in diameter. The exposed, or surface, area of soil in each rim was 
therefore one ten-thousandth of an acre. The rims, after being 
coated with asphaltum, were placed in the open and rested at a 
depth of about 8 inches on natural subsoil, which was a heavy, 
reddish colored clay loam, poor in organic matter and in mineral 
nutrients, as is characteristic of soils from the dolomitic formation 
found in this State. 

Table i. — Mechanical analysis of a Cumberland loam soil from the University 



The mechanical analysis is not that of the lot used in the rim experiments, 
but of the same type from another part of the farm. 

The surface soil used in the experiments was screened and thoroly 
mixed before placement in the rims. Sixty pounds were then placed 
in each rim. distributed evenly, and lightly tamped, thus furnishing 
a lower or absorbing layer about 2 inches thick, with which neither 
lime nor manure was mixed. The various treatments as shown 
in Table 5 were then carefully and thoroly mixed with the balance 
of the soil, 177.5 pounds, for each rim. The total weight of soil 
used per rim was, therefore, 237.5 pounds at time of placement, but 
represented only 200 pounds of moisture- free soil. The total depth 

of loosely compacted soil was about 8 inches. 

hi all, I2<S of the rims were used, these being divided into 

four ' i of 32 each. The lime and manure treatments were identical 

for each set, that LS, the treatments were replicated four times. 

There was a radical difference, however, in the cropping and handl- 
ing of the sets. The first set of .V. scries K, was cropped in Lespc- 
<]• /.i the first year and in compcas for the next three years. Series L 
wai left Undisturbed except thai the weeds were scraped off from 



Farm at Knoxville, Tenn. a 



Percent. 



Fine gravel, 2-1 mm 

Coarse sand, 1-0.5 rnm .... 
Medium sand, 0.5-0.25 mm 
Fine sand, 0.25-0.10 mm .... 
Very fine sand, 0.10-0.05 mm 

Silt, 0.05-0.005 mm 

Clay, 0.005-0 mm 



1. 14 
2.37 
3-32 
9-15 
17.68 
47.85 
18.49 



MOQERS & M'lNTYRE: EFFECTS OF LIME ON SOIL. i8j 

time to time- with a hoe. This set became covered with a light 
growth of moss durng the cooler seasons of the year. Series M 
was uncropped but the soil was turned over and mixed to a depth 
of nearly 6 inches twice a year and the surface 3 inches was stirred 
from time to time thruout the summer season about as would be 
done in the cultivation of a corn crop. The fourth series, X, was 
seeded to tall oat grass, which grew thriftily thruout the period of 
the experiments. 

Table 2. — Chemical analysis of Cumberland loam used in the experiments. 
{Hydrochloric acid 1.11$ sp. gr. used as solvent 
for mineral constituents.) a 



Percent. 

Insoluble residue 86.2000 

Potash (K 2 0) .2300 

Lime (CaO) 1200 

Magnesia (MgO) 3800 

Manganese oxid (MnO) 0800 

Ferric oxid (Fe-Os) 3.0700 

Alumina (Al»Os) 5.1300 

Phosphoric acid (P-0 3 ) 0500 

Total nitrogen (N) 1109 



a Results on moisture-free basis. 

THE CALCIC AND MAGNESIC MATERIALS APPLIED. 

Five forms or kinds of liming materials were used on a chemically 
equivalent basis, as determined by analyses of the materials. Each 
material was applied at each of two rates, 2 and 8 tons of CaO per 
2,000,000 pounds of soil, which was taken as an acre of surface soil. 
The five forms were: Burnt lime, hydrated lime, precipitated car- 
bonate, ground limestone, and ground dolomite. These materials 
were in every case very thoroly mixed with the upper 6 inches of 
soil before placement. The applications at the rates mentioned were 
made, however, under each of two conditions, viz, with and without 
the addition of farmyard manure. The manure was weighed out 
and applied in an air-dry condition after, having been ground in a 
feed mill and then thoroly mixed. From Table 5 it may be seen that 
the manure was applied both with and without the various calcic 
materials at each of three rates, viz, 300 grams, 750 grams, and 
1,200 grams per rim. These amounts correspond to approximately 
12, 30, and 48 tons of fresh manure per acre. All these applications, 
both of the calcic materials and the manure, were made only once in 
the 5-year period, as previously indicated. 



1 88 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



In addition to the calcic materials, two rims in each series received 
precipitated magnesium carbonate, one rim with and one without 
the addition of manure at the 750 gram rate. 

CHEMICAL COMPOSITION AND MECHANICAL MAKEUP OF THE MATERIALS APPLIED. 

The detailed chemical analyses of the inorganic materials used 
are given in Table 3. As to the mechanical composition of the 
inorganic materials, the burnt lime was ground to a fine but granular 
condition before application. Both the hydrated lime and the pre- 
cipitated were in very fine form of subdivision, but tho flocculated 
to some extent were disseminated probably the best of all thruout 
the soil in mixing. In the case of both the ground limestone and the 
ground dolomite, only that part which passed thru a 10-mesh sieve 
was used. Also, the proportions of the particles passing thru various 
sieves were arbitrarily made the same as follows : 

Percent. 

10-mesh to 2 mm 30-69 

2 mm. to 1 mm 18.73 

1 mm. to 0.5 mm 18.55 

Less than 0.5 mm 3 2 -03 

There was, however, an inherent difference in the structure of 
these two materials, the dolomite being harder and less readily re- 
duced to powder than the limestone, so that the mechanical condition 
of the separates can not be considered as identical. 



Table 3.— Chemical analyses of calcic and magncsic materials used in rim 

studies. 



Lab. 
No. 


Material. 


CaO. 


MgO. 


CO2. 


Loss 
on ig- 
nition. 


Ca- 

co«. 


Mg- 

CO3. 


Si0 2 . 


Fe 2 Os 
and 
AI2O3. 






Pet. 


Pet. 


Pel. 


Pet. 


Pet. 


Pet. 


Pet. 


Pel. 


2SI4- • 


Burnt lime 


8423 


o.55 


0.65 


14.10 


1.47 





0.06 


o-53 


2515. • 


Hydrated lime 


7380 


•45 


1-39 


25.22 


3.16 





.05 


•35 


25»6. . 


Precipitated CaCOs 


54-88 


• 73 


43-12 


43-50 


98.00 





.20 





2518. . 


Limestone 


50.20 


.98 


39-88 




89.64 


2.04 


5.88 


1.60 


2519- 


Dolomite 


31.57 


19.03 


44.40 




50.37 


39-09 


3.65 


•85 


2520. . 


|'re« ipitated \J.-( < ) 





42.63 


38.75 


57-io 





"66.87 


-30 






15.40 MgfOHh- 



I Ml. H.J« I.NT.Vil S OF INITIAL SOI I. N ITIUK.KN. 



< r avc 



'I Ik- analyses "l -even different samples of the original soil 
o 1 ]<*) as the average percentage of nitrogen when calculated to 
a moisture In < basis. The admixture of either a calcic material 
fir of manure would, of course, change this percentage. The manure 
a- applied \va- found to contain 1.535 percent of nitrogen and 20.5 



mooers & m'intyre: effects of lime on soil. 



percent of moisture and would, therefore, increase the nitrogen con- 
tent of the soil. On the other hand, the addition of the inorganic 
materials would dilute the soil and lower the percentage of nitrogen. 

The calculation of the exact change which should be allowed for 
this dilution is not easily made because of the chemical changes 
quickly affecting the materials applied. The oxid of lime is almost 
immediately converted to hydrate, this is soon converted into cai~ 
bonate, at least where the light applications were made, and the 
carbonate in turn is slowly silicated, with loss of carbon dioxid. In 
a similar manner the precipitated carbonate, the ground limestone, 
and the ground dolomite are gradually converted into silicates. As 
a basis for this calculation, the writers have taken 328 grams to be 
the average amount of inorganic matter added by the lighter appli- 
cations, the 2-ton rates. On the basis mentioned, calculations have 
been made with regard to the percentage content of nitrogen under 
the various experimental conditions. The results are given in Table 

Table 4. — Percentages of total nitrogen in the soil of the rims at the outset 



of the experiments on moisture-free basis {samples taken 
from total soil to 8-inch depth). 

Experimental condition. Percent. 

Untreated soil 0.1109 

Soil with 328 grams of calcic material 1105 

Soil with 1,312 grams of calcic material 1093 

Soil with 300 grams of manure H57 

Soil with 750 grams of manure 1228 

Soil with 1,200 grams of manure 1298 

Soil with 328 grams of calcic material and 300 grams of manure 11 53 

Soil with 328 grams of calcic material and 750 grams of manure 1225 

Soil with 1,312 grams of calcic material and 1,200 grams of manure 1280 

Soil with 1,238 grams of magnesium carbonate and 750 grams of manure .1211 



Changes in the Nitrogen Content of the Soil, 
the soil sampling. 

Five years from the time the soil was placed in the rims under 
the various experimental conditions, samples were taken from each 
rim for the entire, or 8-inch, depth. These samples were analyzed 
for total nitrogen by the unmodified Kjeldahl method, using 10- 
gram charges of soil for each determination. The analytical results 
obtained by averaging duplicate determinations and calculated to 
a moisture-free basis are given in Table 5. 



190 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 5. — Nitrogen content of soil at end of 5-year period under various 

conditions. 

SERIES K, JAPAN CLOVER AND COWPEAS. 







Treatment. 


Nitrogen on 
moisture-free 


Rim No. 




Quantity 








Liming material. 


per rim. 


Manure. 


oasis. 








Grams. 


Grams. 


Percent. 


K 


I 


Burnt lime 


181.44 




0.0996 


K 


2 


Hydrated lime 


244.24 




.1008 


K 


3 


Precipitated carbonate 


323.92 




.0967 


K 


4 


Ground limestone 


354-68 




.0998 


K 


5 


Ground dolomite 


305-62 




.1001 


K 


6 


None 






.1023 


K 


7 


Burnt lime 


181.44 


300 


.1016 


K 


8 


Hydrated lime 


244.24 


300 


•1033 


K 


9 


Precipitated carbonate 


323-92 


300 


.1023 


K 


10 


Ground limestone 


354-68 


300 


.1051 


K 


11 


Ground dolomite 


305.62 


300 


.101 1 


K 


12 


None 




300 


.1028 


K 


13 


Burnt lime 


181.44 


750 


.1043 


K 


14 


Hydrated lime 


244-24 


750 


.1031 


K 


15 


Precipitated carbonate 


323.92 


750 


.1036 


K 


16 


Ground limestone 


354-68 


750 


•1057 


K 


17 


Ground dolomite 


305.62 


750 


.1043 


K 


18 


None 




750 


.1089 


K 


19 


Burnt lime 


725.76 


1,200 


.1001 


K 


20 


Hydrated lime 


976.94 


1,200 


.0991 


K 


21 


Precipitated carbonate 


1,295.68 


1,200 


. 1 03 1 


K 


22 


Ground limestone 


1,418.72 


1,200 


.1038 


K 


23 


Ground dolomite 


1,222.48 


1,200 


.1046 


K 


24 


None 




1,200 


.1143 


K 


25 


Burnt lime 


725.26 




.0874 


K 


26 


Hydrated lime 


976.94 




.0859 


K 


27 


Precipitated carbonate 


1,295.68 




.0930 


' K 


28 


Ground limestone 


1,418.72 




.0965 


K 


29 


Dolomite 


1,222.48 




•0957 


K 


30 


None 






.1036 


K 


31 


Magnesium carbonate 


1,238.07 




.0993 


K 


32 


Magnesium carbonate 


1.238.07 


750 


.1048 


SKRIKS L, NO CROP, SOIL UNDISTURBED 






Burnt lime 


181.44 




.0950 




2 


Hydrated lime 


244.24 




•0957 




3 


Precipitated carbonate 


323-92 




.0942 




4 


Ground limestone 


354-68 




.0998 




5 


Ground dolomite 


305.62 




.0942 




6 


None 






.103 1 




7 


Burnt lime 


181.44 


300 


.0976 




8 


1 I ydrated lime 


244.24 


300 


.0950 




9 


l're ( ipituted carbonate 


3*3»9a 


300 


.0983 




to 


( iround limestone 


354-68 


300 


.1043 




1 1 


( iround dolomite 


305.62 


300 


.1008 




12 


None 




300 


.1038 




13 


Burnt lime 


181.44 


75o 


.1036 




14 


Hydrated lime 


34424 


75o 


.1016 




IS 


I'm < jpitated ( arbonate 


32392 


750 


.1026 




16 


( iround limestone 


354-08 


7 JO 


. 1 007 




17 


1 rround dolomite 


305. <)2 


750 


.1087 




18 


None- 




75o 


.1059 




19 


BUTOi lime 


725.76 


1 ,200 


.1013 




20 


Hydrated lime 


070.04 


1,200 


.1026 




2 1 


Pn ' Ipitated < arbonate 


1 ,295.68 


1 ,200 


.1048 



mooers & mtxtyre: effects of lime ox soil. 191 



Table 5 (continu ed) . 







Treatment. 




-Nitrogen on 












Rim Xo. 


Liming material. 


Quantity 




moisture-free 






per rim. 


Manure. 


basis. 








Grams. 


Grams. 


Percent. 


L 


22 


Ground limestone 


1,418.72 


1,200 


.1041 


T 


23 


Ground dolomite 


1,222.48 


1.200 


.1001 


L 


24 


Xone 




1,200 


.1092 


jr 


2 5 


Burnt lime 


725.26 




.0889 


L 


26 


Hydrated lime 


976.94 




.0856 


L 


2 7 


Precipitated carbonate 


1,295.68 




.0912 


L 


28 


Ground limestone 


1,418.72 




.0950 


L 


29 


Dolomite 


1,222.48 




•0945 


L 


3° 


Xone 






.1062 


L 


3 1 


Magnesium carbonate 


1,238.07 




.0965 


L 


3 2 


Magnesium carbonate 


1,238.07 


750 


.1013 






SERIES If a XO CROP, SOIL STIRRED 




M 


1 


YK 1 1 TTl r llTTli 


T«T a a 

101.44 




.0976 


M 


2 


JTx \ Lll clLtrU. IlIIlc 


244-24 




•0935 


M 


3 




323.92 




.0978 


M 


4 


Ground limestone 


334.05 




.0942 


M 


5 


vjiuuiiu uuiuiin lc 


305.62 




.1003 


M 


6 








.1028 


M 


7 


Burnt lime 


I8I.44 


300 


.0976 


M 


8 


Hydrated lime 


244.24 


300 


.0986 


M 


9 


Precipitated carbonate 


323 92 


300 


.0996 


M 


10 


Ground limestone 


354-68 


300 


.1006 


If 


11 


Ground dolomite 


305-62 


300 


.0981 


M 


12 


Xone 




300 


.1048 


M 


13 


Burnt lime 


181.44 


750 


.0983 


if 


14 


Hydrated lime 


244.24 


750 


.0976 


M 


15 


Precipitated carbonate 


323 92 


750 


.0927 


If 


16 


Ground limestone 


354-68 


750 


.1031 


If 


17 


Ground dolomite 


305-62 


750 


.1059 


M 


18 


Xone 




750 


.1087 


M 


19 


Burnt lime 


725-76 


1,200 


•0935 


M 


20 


Hydrated lime 


976.94 


1,200 


.0920 


If 


21 


Precipitated carbonate 


1,295.68 


1,200 


.0996 


M 


22 


Ground limestone 


1,418.72 


1,200 


.0986 


M 


23 


Ground dolomite 


1,222.48 


1.200 


.0988 


a r 

_M 


24 


Xone 




1,200 


.1097 


A r 

-M 


25 


Burnt lime 


725.26 




.0805 


\[ 




Hydrated lime 


976.94 




.0824 


AT 

-\1 


2 7 


Precipitated carbonate 


1,295.68 




.0912 


at 


28 


Ground limestone 


1,418.72 




.0917 


-\1 


29 


Dolomite 


1,222.48 




.0917 


a r 


30 


Xone 






.1021 


a r 


31 


Magnesium carbonate 


1,238.07 




.0886 


M 


^ 


Magnesium carbonate 


1,238.07 


750 


.1023 






SERIES N, TALL 


OAT GRASS 






X 


I 


Burnt lime 


I8I.44 




.1107 


X 


2 


Hydrated lime 


244.24 




t nn 1 


X 


3 


Precipitated carbonate 


323-92 




.1114 


X 


4 


Ground limestone 


354-68 




.II02 


X 


5 


Ground dolomite 


305.62 




.1109 


X 


6 


Xone 






.1051 


X 


7 


Burnt lime 


181.44 


300 


.1153 


X 


8 


Hydrated lime 


244-24 


300 


•I 145 


X 


9 


Precipitated carbonate 


323 92 


300 


.1143 



192 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 5 (continued). 



Rim No. 


Treatment. 


Nitrogen on 
moisture-free 
basis. 


Liming material. 


Quantity 
per rim. 


Manure. 








Li? CUTIS . ' 


(jY awis . 


.£ cyccnt. 


N 


10 


IvIYVlinn limpof Ano 
Vti UUI1L1 lIIllcl>LOIie 


354-°° 


300 


•1153 


N 


1 1 


Ground dolomite 


305.62 


300 


.1163 


N 


1 2 


None 




300 


ttaQ 

. 1 190 


N 




Burnt lime 


181.44 


750 


. 1 209 


N 


14 


Hydrated lime 


244- 2 4 


750 


. I 229 


N 


15 


Precipitated carbonate 


323-92 


75o 


.1214 


N 


16 


Ground limestone 


354-68 


750 


. 1 291 


N 




Ground dolomite 


305.62 


750 


. 1 190 


N 


18 


None 




75° 


• 1173 


N 


19 


Burnt lime 


725.70 


1,200 


. 1 1 70 


N 


20 


Hydrated lime 


976.94 


1 ,200 


• IT 43 


N 


21 


Precipitated carbonate 


1,295.68 


1 ,200 


.1203 


N 


22 


Ground limestone 


1,418.72 


1 ,200 


.1211 


N 


23 


Ground dolomite 


1,222.48 


1,200 


.1216 


N 


24 


None 




1,200 


.1183 


N 


25 


Burnt lime 


725.26 




.1016 


N 


26 


Hydrated lime 


976.94 




.1036 


N 


27 


Precipitated carbonate 


1,295.68 




.1074 


N 


28 


Ground limestone 


1,418.72 




.1117 


N 


29 


Dolomite 


1,222.48 




.1082 


N 


30 


None 






.1140 


N 


3 1 


Magnesium carbonate 


1,238.07 




.1036 


N 


32 


Magnesium carbonate 


1,238.07 


750 


.1170 



DISCUSSION OF THE SOIL RESULTS. 

Iii work of this kind too much importance should not be attached 
to the nitrogen content of a single rim, because of errors in the 
sampling and in the analytical work, together with possible acci- 
dental and unknown happenings which may easily distort a true 
result. Even the averages from two or three rims, as given in Table 
6, may be in error for the same reason, but can be used with at 
leasl a larger degree of confidence. So far as these series are con- 
cerned, presentation as in Table 6 serves to strengthen materially 
some of the more important conclusions reached from the results 
considered as a whole. 

To facilitate the comparison of the various averages as given 
in tlii- table, h-inr | to X were prepared. In the charts the height 
of the black columns indicates the percentage of nitrogen at the end 
of the 5-year period. The white columns show the percentages of 
nitrogen at the outset after the various forms of lime and the 
mannrial treatments were made. 

If tie- firsl four charts, figures 4 to 7. are compared together the 
strikingly higher percentages of nitrogen in the soil of series N 
at the end of the 5 \ ear period is evident, The average percentage 



mooers & m'intyre: effects of lime on soil. 



193 



Table 6. — Nitrogen content of soil summarized under various experimental 
conditions at end of 5-year period (Nitrogen percentages 
calculated to moisture-free basis). 





Fresh 
manure 
per acre. 


Lime 


Nitrogen content of soil to which calcic 


□r other material was applied. 


Series. 


equiv- 
alent 
per 
acre. 


None. 


Burnt 
lime. 


Hydrated 
lime. 


Precipi- 
tated car- 
bonate of 
lime. 


Lime- 
stone. 


Dolomite. 


Magnes- 
ium car- 
bonate. 


K 
K 
K 


Tons. 
None 
12 

30 

Average 


Tons. 
2 
2 

• 2 


Percent. 


Percent. 

0.0996 
.1016 
.1043 
.1018 


Percent. 

O.IO08 
.1033 
.1031 
.1024 


Percent. 

0.0967 
.1023 
.1036 
.1009 


Percent. 
0.0998 
.1051 

• IOS7 

• 1035 


Percent. 

O.IOOI 

.1011 
.1043 
.1018 


Percent. 


K 
K 


None 
48 
Average 


8 
8 




.0874 
. 100 1 
.0938 


.0859 
000 1 
.0925 


.0930 
.1031 
.0981 


.0965 
.1038 
.1002 


•0957 
.1046 
.1002 




K 
K 


None 
30 

A VPH crp 


8 
8 


■ 












0.0993 
.1048 
.1021 


K 
K 
K 


None 
12 
30 
Average 


None 
None 
None 


.1030 
.1028 
.1089 
.1049 














K 


None 

. 48 

Average 


None 
None 


.1030 

.1143 
.1087 




















NO CROP SOIL 


UNDISTURBED. 








L 
L 
L 


None 
12 
30 
Average 


2 
2 
2 




.0950 
.0976 
.1036 
10987 


•0957 
.0950 
.IOl6 
.0974 


.0942 
.0983 
.1026 
.0984 


.0998 
.1043 
.1067 
.1036 


.0942 
.1008 
.1087 
.1012 




L 
L 


None 
48 
Average 


8 
8 




.0889 
.1013 
.0951 


.O856 
.1026 
.0941 


.0912 
.1048 
.0980 


.0950 
.1041 
.0996 


.0945 

.1001 

.0973 




L 
L 


None 
30 
Average 


8 
8 














.0965 
.1003 
.0989 


L 
L 
L 


None 
12 

Average 


None 
None 
None 


.1047 
.IO38 
.1059 
.IO48 














L 
L 


None 
48 
Average 


None 
None 


.1047 
.IO92 
.1070 















194 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 6 (continued). 





Fresh 
manure 
per acre. 


Lime 


Nitrogen content of soil to which calcic or other material was applied. 


00 
'£ 

3 
t: 


equiv- 
alent 
per 
acre. 


None. 


Burnt 
lime. 


Hydrated 
lime. 1 


Precipi- 
ated car- 
bonate of 
lime. 


Lime- 
stone. 


Dolomite. 


Magnes- 
ium car- 
bonate. 








NO 


CROP, SOIL CULTIVATED. 








M 
M 
M 


12 

30 
Average 


2 

2 
2 




.0976 
.0976 
.0983 
.0978 


•0935 
.0986 
.0976 
.0966 


.0978 
.0996 
.0927 
.0967 


.0942 
.1006 
.1031 
•0993 


.1003 
.0981 
.1059 
.1014 




M 
M 


None 
48 
Average 


8 

8 




.0805 

•0935 
.0870 


.0824 
.0920 
.0872 


.0912 
.0996 
•0954 


.0917 
.0986 
.0952 


.0917 
.0988 
•0953 




M 
M 


None 
30 
Average 


8 
8 














.0886 
.1023 
•°955 


M 
M 
M 


None 

12 

30 
Average 


None 
None 
None 


.1025 

.IO48 
.1087 
•1053 














M 
M 


None 

4° 

Average 


None 
None 


.1025 
.1097 
.I06l 






















TALL 


OAT GRASS. 








N 
N 
N 


12 

30 
Average 


2 
2 
2 




.1107 

•1153 
.1207 
.IISO 


.1094 
•I 145 
.1229 
.1156 


.1114 
•1 143 
.1214 

•1157 


.1102 

."S3 
.1291 
.1182 


. .1109 
.1163 
.1190 
•1154 




N 
N 


None 
48 
Average 


8 
8 




.1016 
.1170 
.1093 


•.IO36 

•I 143 
.1090 


.1074 
.1203 
•1139 


.1117 
.1211 
.1164 


.1082 
.1216 
.1149 




N 
N 


30 
Average 


8 














.1036 
.1170 
.1103 


N 
N 
N 


None 

12 

30 

Average 


None 

None 
None 


.1 140 
.1198 

.1173 
.II70 














N 
N 


None 
41 
Average 


None 
None 


.1140 
.U83 
.1162 















of nitrogen for series X is 0.1144, bul the average from the other 
• : ree erica is only 0.0993. explanation of this result, attention 

i called i" tin- fad llial tall oat .^r.'iss makes a vigorous growth 
in lhi> climate and remains green almost thruoul the year. A])- 



mooers & m'intyre: effects of lime on soil. 



195 



.1200 



.1100 



n 

Fig. 4. Effect of various forms of lime on the nitrogen content of the soil; 
Series K, crops grown, lespedeza and cowpeas. In figures 4 to 7, the left half 
of the graph shows the results from the application of 2-ton equivalents, and 
the right half of 8-ton equivalents. In each half, the white column at the left 
represents the original nitrogen content. The results from the various appli- 
cations are shown in the following order: No lime; burnt l'me; hydrated lime; 
precipitated carbonate ; ground limestone ; and dolomite. 



1200 



.1100 



o .1000 



.0900 



0800 



Jfflttliali 

Mill Mill 



Fig. 5. Percentages of nitrogen in soil in Series L, no crop, soil undisturbed. 
See legend to figure 4. 



I96 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



.1200 




0800 



Fig. 6. 
See legen 



Percentages of nitrogen in soil in Series M, no crop, soil cultivated, 
d to figure 4. 



.1200 



1100 



S .1000 



.0900 



0800 




I ill 




Ik.. 7. I'< r< cntages of nitrogen in soil in Scries N, tall oat grass. Se< 

legend to figure 4. 



mooers & m'intyre: effects of lime ox soil. 



197 



parently, therefore, it conserves the soil supply of nitrogen to much 
greater extent than the cowpea, which, tho a vigorous legume, is an 
annual growing only thru the summer season, the soil being bare 
thru out the rest of the year, so that a large loss of nitrogen by 
leaching would be expected. A slightly larger amount of soil 
nitrogen was found in series K, where the cowpeas were grown, 
than in either series L or M, which were uncropped. Series L, 
which was undisturbed, except to scrape oft or pull up any weed 
growth that started, showed a somewhat higher content of nitrogen 
than series M, which was cultivated each year. The average per- 
centage of nitrogen for each series is 0.1008 for K, 0.0995 for L, and 
0.0969 for M. . In the consideration of the outcome from series L 
and M, attention is called to the fact that moss more readily covered 
the soil of series M than of any other and it is possible that this 
growth, tho at no time heavy, had a conserving effect on the nitrogen 
content of the soil. At any rate, the greater moss growth on series 
L, as well as the frequent stirring of the soil in series M, should be 
taken into consideration in the interpretation of the slight difference 
in the outcome of these two series. 

In all four series an appreciably greater loss of soil nitrogen is 
evident under the 8-ton equivalents than under the 2-ton. This 
is true either with or without the addition of manure. Also it is true 
of each kind of liming material but is especially noticeable where 
either the oxid or the hydrated forms were applied. 

In series K, L, and M, the 2-ton equivalents accelerated the loss 
of nitrogen, but in series X, where the tall oat grass grew, practic- 
ally the same amount of nitrogen was found at the end of the 
five years as at the outset. It may even be said that, within the limits 
of error, there was no decrease in the percentage of total soil nitro- 
gen in spite of the known quantity removed by the crops and the 
loss by leaching, which must have been considerable. As no legumes 
were allowed to grow in this series, nitrogen fixation, by azotabacter 
or the like, is strongly suggested. 

Figures 4 to 7 and Table 7 show that there is no significant 
difference between the effects of burnt lime, hydrated lime, and 
precipitated carbonate when applied on the 2-ton basis, the average 
percentage of nitrogen for all four series being 0.1035 for the burnt 
lime, 0.1030 for the hydrated lime, and 0.1029 for the precipitated 
carbonate, as compared with 0.1080 where no lime was applied. All 
three forms, therefore, occasioned a material reduction in the nitro- 
gen content of the soil. Where the relatively coarse limestone and 



I98 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



dolomite were applied appreciable losses of nitrogen resulted, but 
less than for the other forms, the percentages being 0.1062 for the 
limestone and 0.1050 for the dolomite. Under the 8-ton treatments 
greater losses of soil nitrogen took place in all cases. Burnt lime 
and hydrated lime gave almost duplicate outcomes, the percentage 
of nitrogen being 0.0963 for the former and 0.0957 for the latter. 
Inn the effects of the precipitated carbonate, instead of being in har- 
mony with the oxid and hydrate, were in close accord with the results 
from the limestone and dolomite, the percentages of nitrogen being 
0.1014 for the precipitated carbonate, 0.1029 for the limestone, and 
0.1019 for the dolomite. 



Table 7. — Nitrogen content of soil following various lime treatments, as shown 
by soil samples at close of 5-year period (All series averaged, 12 
rims for each 2-ton rate and 8 rims for each 8-ton rate). a 



Rate of 
liming. 


Lime treatments. 


None. 


Burnt 
lime. 


Hyd rated 
lime. 


Precipitated 
carbonate. 


Ground 
limestone. 


Ground 
dolomite. 


2 -ton 

8-ton 


Percent. 
0.1080 
.1095 


Percent. 
0.1035 
.0963 


Percent. 
0.1030 
.0957 


Percent. 
0.1029 
.1014 


Percent. 
0.1062 
.1029 


Percent. 
0.1050 
.1019 



a Nitrogen content at outset: 2-ton basis, 0.1161 percent; 8-ton basis, 0.1187 
percent; but without lime. 0.1165 percent and 0.1195 percent, respectively. 



That the oxid and hydrate should show closely agreeing effects 
thruout the series is not surprising, for the oxid would be almost 
immediately hydrated in the soil. Their action appears to be identi- 
cal. Madntire (4) a found that both oxid and hydrated lime applied 
at the 2-ton rate attained maximum carbonation in the course of 
5 days. It is not strange, therefore, that these three forms should 
give similar result when applied at the low rate. Just why the pre- 
cipitated carbonate, when applied at the 8-ton rate, should produce 
results different from those obtained from the same equivalents 
"i oxid and hydrate, but similar to those from the ground limestone 
and ground dolomite, is not altogether clear. More time was re- 

quired for the oxid and hydrate to carbonate. The carbonate form 

a] \\a- found to persist in the soil under the <X-ton but not under 
the 2 inn application, that is, the latter silicated long before the 
former, (he quantity being too great to be quickly changed over. The 
!■'< I'i'i.'c r to " Literature cited," p. 205. 



mooers & m'intyre: effects of lime on soil. 



199 



results from the heavy applications warrant the conclusion that 
both the oxid and the hydrate increased appreciably the outgo of 
nitrogen as compared with the other forms used. 

Precipitated magnesium carbonate, which was applied at the 8-ton 
rate both with and without manure, induced losses of soil nitrogen 
comparable to those which followed liming with precipitated calcium 
carbonate. This result can well be seen from figure 8, in comparison 
with figures 4 to 7. 



Results Obtained Elsewhere. 



.1200 



1100 



.1000 



r 



Numerous results obtained at the New Jersey station have shown 
that liming with ground oyster shells may produce decided losses of 
soil nitrogen. In a rotation of corn, oats, wheat, and timothy, the 
limed plats were found to have lost, in 10 years, 240 pounds more 
nitrogen per acre than the unlimed plats (3). In another experi- 
mental series (2), with timothy and clover, the content of soil nitro- 
gen appeared to be increased on 
range 1, but to have remained con- 
stant on range 2. On range 3, with 
rye. vetch, and crimson clover, the 
effect of liming on the nitrogen 
content of the soil was not appreci- 
able. On the other hand, on range 
4. where rye, cowpeas, oats, and 
peas took the place of timothy and 
clover, the limed soil lost nitrogen 
as compared with the unlimed. In 
these experiments the authors state, 
"The limed plots, with only slight 
exception, have yielded distinctly 
larger crops and more total nitrogen 
than the unlimed plots." 

In these New Jersey experiments 
it seems evident that liming pro- 
duced loss of soil nitrogen where original and Series K, L, M, and N. 
no legume was grown or even where certain legumes were grown, 
but that with such legumes as red clover and crimson clover the gains 
in nitrogen might offset or even more than offset the losses produced 
by liming. 



.0900 



1111 



.0800 

Fig. 8. Results with magnesium 
carbonate, 8-ton equivalents. Col- 
umns from left to right represent 



200 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



At the Pennsylvania station, as a part of their general fertilizer 
series of experiments, begun in 1881, studies were made of the 
effects of applications both of burnt lime and of ground limestone. 
The burnt or caustic lime was applied at the rate of 2 tons per acre 
once every four years and the ground limestone at the same rate 
every two years, so that the chemical equivalents were practically 
the same. In 1899, or eighteen years after the experiments were 
begun, the soil from the variously treated plats was analyzed by 
Hess and again in 191 1 by Maclntire, particular attention being 
given in each instance to the determination both of nitrogen and of 
organic matter. 

The conclusions reached by Hess are stated by Frear (1) as 
follows : 

1. That lime alone has a markedly destructive effect, direct or indirect, upon 
the soil humus. 

2. That a like destructive action occurs, as would be anticipated when lime is 
used with manure, as shown by comparison with the soil that received a like 
manure dressing without lime. 

3. That carbonate of calcium is less destructive, since the soil of plat No. 34 
shows considerably more humus than the untreated soil. 

Unfortunately no soil samples were taken at the outset of these 
experiments so that the original humus content is not known, hence 
the results gotten by Hess do not furnish the conclusive evidence 
desired. 

The two sets of nitrogen determinations, as given in Table 8, are 
taken from Bulletin 261 of the Pennsylvania State Department of 
Agriculture (p. 149), The analyses made by Maclntire of the 191 1 
samples, while confirmatory of the figures obtained so far as nitro- 
gen and humus contents of the soils under the various treatments 
Ivere concerned, showed that in the 12 years which had inter- 
vened probably no material changes had taken place in the relative 
nitrogen content of these plats. Three of them indicated a gain and 
the other two a loss, but there was no indication that the burnt lime 
had produced, in the [2-year period, a greater loss of nitrogen than 

the ground limestone. hi connection with these, experiments it 
should be mentioned thai the plats were large .and somewhat lacking 
in uniformity, making sampling difficult, so thai entirely concordant 

Iti from sampling conducted bj different men would not be ex- 

peeted. 

Perhapfl both Betfl of conclusions were right, that is, there may 
I vi hern a yvc: t er !<--. of nitrogen for the first term of years from 



mooers & m'intyre: effects of lime ox soil. 



201 



the caustic lime than from the ground limestone, but in the last term 
of years the ground limestone caused as much or more loss than the 
burnt lime. Results suggesting such a possiblity have been obtained 
in the cowpea-wheat rotation experiments at the Tennessee station 
and will be referred to later. 



Table 8. — Nitrogen content of soil from certain plats of the general fertilizer 
experiments at the Pennsylvania station (Pa. Dept. Agr., Bui. 261, p. 156). 



Plat treatment. 


Hess, 
1899-1900. 


Maclntire, 
1911. 


Change in 
12 years. 




Percent. 


Percent. 


Percent. 


Cntreated soil 


0.1244 


a 0.II22 


— 0.0122 


Manure (6 T.) 


.1508 


.1523 


.0015 


Manure (6 T.) and lime 


.1468 


.1589 


.1021 


Lime 


.1172 


.1199 


.0027 


Ground limestone 


•I34i 


.1222 


— .0119 



a Representing Plats 24 only, the four untreated plats adjacent to the four 
limed plats, whereas the 1899-1900 samples represented Plats 1, 14, 24, and 36 
collectively. 



Attention will now be called to the results obtained from field 
experiments at the Tennessee station (5) on a soil similar to that 
used in the rims. Liming with burnt lime at the rate of 1,800 pounds 
per acre very materially increased the losses of soil nitrogen under 
each of a number of experimental conditions, such as the continued 
removal of all crops, the turning under of the cowpea crop, and the 
removal of only the wheat crop. The limed plats lost nearly 20 
pounds more of nitrogen per annum than the unlimed for the first 5 
years. Since that time unpublished data show that the differences 
between the percentages of nitrogen in the limed and unlimed plats 
graduallv became less and less until in the course of 10 vears from 
the beginning of the experiment there was no appreciable difference 
between them. A second application of burnt lime at the end of 12 
years failed to change the situation in the following two years. 
Therefore, in conclusion, the writers wish to emphasize the point 
that while liming may produce marked changes in the content of 
soil nitrogen for a few years, after the initial liming there is at least 
the possibility that these differences may disappear later. 

The Crop Yields. 

One crop of lespedeza and three crops of cowpeas, all harvested 
at the hay stage, were grown on series K. On series X tall oat grass 
was grown continuously. All the crops were removed. The yields of 



202 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



lespedeza on series K were very irregular, due in large part to the 
very uneven stands obtained. There was also some trouble with the 
cowpeas in this respect. The stands of tall oat grass were excellent 
almost thruout the series. The yields are summarized in Table 9, 
which gives the average total hay production per rim, and also the 
nitrogen removed by the hay under each lime treatment specified. 



Table 9. — Summary of yields per rim of lespedeza and cowpea hay and of 
tall oat grass hay, with the nitrogen removed by the 
hays during the 5-year period. 



Form of lime. 


Series K, Lespedeza and 
cowpea hay. 


Series N, Tall oat grass 
hay. 


Hay. 


Nitrogen. 


Hay. 


Nitrogen. 




Grams. 


Grams. 


Grams. 


Grams. 


2-ton basis: 










Burnt 


934-7 


23.04 


690.4 


8.23 


H yd rated 


933-0 


23.16 


718.6 


8.58 


Precipitated 


818.8 


20.60 


626.5 


7-56 


Limestone 


775-7 


19.62 


659-0 


7-77 


Dolomite 


969.8 


24.18 


571-3 


6.85 


None 


461.4 


11.06 


436.0 


5-35 


8-ton basis: 










Burnt 


796.9 


21.02 


841. 1 


9-83 


Hydrated 


728.9 


19.26 


937-5 


10.96 


Precipitated 


732.0 


18.40 


847-4 


9.90 


Limestone 


1.093-3 


26.50 


849-3 


9-93 


Dolomite 


1,100.0 


26.78 


814.4 


9-54 


None 


733-4 


18.46 


574-1 


6.89 




839-8 


21.01 


713-8 


8-45 



DISCUSSION OF THE CROP RESULTS. 

Because of the uneven stands obtained in series K, special stress 
call not be laid on the legume yields. It is evident, however, that 
billing with any material appreciably increased the yields, tho at the 
8-ton rate the burnt lime, hydrated lime, and precipitated carbonate 
gave low yield* as compared cither with those obtained at the 2-ton 
rati of the same materials or at the <S-ton rates of limestone and 

dolomite. Thia result is attributed in large part to the highly floc- 
culating effect of the heavy applications of these three materials 
and a COn equenl rapid drying 0U1 of the soil after a rain resulting 
in low germination of the seed. Similar results have been noticed in 
field experiments at the station farm, where a single ton of burnt 
lime has been found to produce an unfavorable effect on the 

itructure of thii particular type of soil so that poor stands of cow- 



mooers & m'intyre: effects of lime on soil. 



203 



peas were obtained, whereas on adjoining unlimed plats the stands 
were normal. 

Perhaps the most important conclusion to be reached from the 
crop results is that the 8-ton applications of both the oxid and 
hydrate forms of lime resulted in appreciable waste of soil nitrogen 
from the cropped series K and N, that is, the losses from the soil 
are not counterbalanced by a corresponding increase of nitrogen 
in the crops. 

In series N liming at either rate materially increased the yfelds 
but no lowering of the yields resulted from the 8-ton treatments of 
either the oxid or hydrate, as was the case with series K. In fact, 
the increases from the 8-ton treatments surpassed those from the 
2-ton in all cases. 

As may be calculated from Table 9, the nitrogen contained by the 
leguminous crops is nearly two and one-half times that found in the 
nonleguminous crops of tall oat grass. In either series if the nitro- 
gen found in the crop be added to that found in the soil at the end 
of the 5-year period, more nitrogen is obtained than was present 
at the outset in the surface soil. The subsoil was rather heavy and 
tenacious and showed on the average a content of 0.0824 percent 
nitrogen in the upper 6 inches. The subsoil would be expected, 
however, to yield nitrogen to the crops grown but, since there are 
no data to show the quantity derived from this source, the matter 
will not be discussed further. * 

EFFECT OF MAGNESIUM CARBONATE ON CROP YIELDS. 

As previously mentioned, the effect of magnesium carbonate on 
the loss of soil nitrogen was similar to that of the precipitated cal- 
cium carbonate. The effect on the crop yields was, however, quite 
different, for the magnesia treated rims produced only scanty crops 
the first year (19.14). Afterwards the normal crops were produced 
by them. 

Summary. 

1. Five forms of lime, viz, oxid, hydrate, precipitated carbonate, 
ground limestone, and ground dolomite, and precipitated magnesium 
carbonate were used in four series of experiments with the object 
of determining their comparative effects on the soil content of total 
nitrogen. The lime materials were applied at each of two rates on 
the basis of 2 and 8 tons per acre of CaO. These applications were 
made both with and without the addition of stable manure. Results 
are reported for the period of the first five years. 

2. The experiments were made in 128 rims exposed to open air 



204 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



conditions. Each rim was i foot deep and 2.225 f eet in diameter, 
the surface area of exposed soil being one ten-thousandth of an 
acre. 

3. Thirty-two rims were used in each of four similarly treated 
series designated as K, L, M and N. 

In series K one crop of lespedeza and three crops of cowpeas 
were grown and removed as hay. In series L no crop was grown 
and the soil was disturbed as little as possible thruout the period. 
In series M no crop was grown but the soil was cultivated from time 
to time thruout the growing season as for corn. In series N tall oat 
grass was grown continuously. 

4. Series K, L, and M all showed marked and very similar losses 
of soil nitrogen. Series N showed the least loss of soil nitrogen. 
At the end of the 5-year period the average percentage of soil nitro- 
gen in the rims of series N was 0.1144, but the average from the 
three other series was only 0.0993. The average percentage of 
nitrogen in a series at the outset was 0.1174. 

5. All forms of lime gave rise to a loss of soil nitrogen, the 8-ton 
iates noticeably surpassing the 2-ton in this respect. 

\t the 2-ton rate the oxid, hydrate, and precipitated carbon- 
ate induced losses similar in extent. These losses were especially 
apparent in series K, L, and M. The 2-ton application of limestone 
and dolomite induced appreciable losses in series K, L, and M, but 
not in series N. 

7. At the 8-ton rate the oxid and hydrate gave rise to large losses 
of soil nitrogen in all scries, especially in K, L, and M. The pre- 
cipitated carbonate, ground limestone, and dolomite produced losses 
which were similar one to the other, but much less than was pro- 
duced by either the oxid or hydrate. 

8. Thruout the scries there was no significant difference between 
the effect <>i the oxid and hydrate, these forms inducing the greatest 
losses, but especially at the higher or 8-ton rate of application, 

<). As might be expected from the relative coarseness of their 
particles, ground limestone and dolomite induced the least loss of 
soil nitrogen. ( >n the other band, the very fine, precipitated carbon- 
ate, while inducing Losses almost identical with the oxid and hydrate 
when applied at the 2-ton rate, ranked with the ground limestone and 
dolomite in producing the smallest losses when applied at the 8-ton 
rate. 

[0 The precipitated magnesium carbonate induced losses com- 
parable witb the precipitated calcium carbonate. 



mooers & m'ixtyre: effects of lime ox soil. 



11. The lespedeza and cowpea crops of series K produced slightly 
more dry matter than the tall oat crops of series L. The nitrogen 
removed by the cowpeas, however, was nearly two and a half times 
that removed by the tall oat grass. 

12. All forms of lime produced greatly increased yields of both 
crops, but distinctions between the effect of the different forms 
can hardly be made. At the 8-ton rate, however, the ground lime- 
stone and dolomite produced much larger yields of cowpeas than 
did any other form, perhaps due to the highly flocculating action of 
the other forms, thus changing, apparently adversely, the soil struct- 
ure. Corresponding influences on yields did not. however, appear 
in the case of the tall oat grass. 

13. The evidence is conclusive that both the oxid and hvdrate 
when applied at the 8-ton rate resulted in a waste of nitrogen, the 
losses being greater from the soil but with no more nitrogen in the 
crops than either precipitated carbonate, ground limestone, or dolo- 
mite were applied. 

14. Under cropping and with liming at the 2-ton rate no one form 
plainly produced a greater loss of soil nitrogen than the others. 

15. Experimental results from the Xew Jersey station show that 
with certain crops, nonlegumes in particular, marked losses of soil 
nitrogen followed liming with ground oyster shells, but that the 
nitrogen loss was entirely overcome where either red or crimson 
clover entered into the rotation. 

16. The results obtained in field experiments at both the Penn- 
sylvania and Tennessee stations indicate the possibility of material 
losses of soil nitrogen following the initial use of burnt lime, but 
with greatly reduced or even no effect of this kind from later liming. 

Literature Cited. 

1. Frear, Wm. Sour soils and liming. Pa. Dept. Agr. Bui. 261. p. 149 1915. 

2. Lipman, J. G., and Blair. A. W. The lime factor in permanent soil im- 

provement. /;/ Soil Sci.. v. 9. no. 5, pp. 9 T - IT 4- 1920. 

3. . Field experiments on the availability of nitrogenous fertilizers, 190S- 

1917. In Soil Sci.. v. 9, no. 5. p. 391. 1920. 

4. MacIntire, W. H. The carbonation of burnt lime in soils. In Soil Sci. 

v. 7, no. 5. pp. 351 and 354. 1919. 

5. Mooers, C. A. The effect of liming and of green manuring on the soil con- 

tent of nitrogen and humus. % Tenn. Agr. Exp. Sta. Bull. 96, pt. 3. pp. 37 
and 43. 1912. 



THE VALUE OF LIMING IN A CROP ROTATION WITH AND 
WITHOUT LEGUMES. 1 



Jacob G. Lipman. 2 

This is a brief record of certain experiments conducted by the New 
Jersey Agricultural Experiment Station. These experiments have 
been in progress for thirteen years and deal in part with the lime 
factor in the transformation and accumulation of nitrogen in soils. 
The land used for these experiments had been neglected for many 
years prior to 1908. The information at hand seems to indicate that 
lime had not been used on this land for 25 or 30 years prior to the 
beginning of the experiments. In fact, there is no evidence that this 
land had ever received an application of lime. At the time of the 
beginning of the experiments lime requirement determinations were 
made by the Veitch method. This showed a lime requirement of 
about 1,600 to 2,000 pounds of lime (CaO) per 2,000,000 pounds 
of soil. 

In the spring of 1908 the field was laid out in twentieth-acre plats. 
These have been used since for nitrogen availability studies as well 
as for nitrogen accumulation studies. Hence, different rotations have 
been employed. Some of them include legumes; others do not. The 
rotation used in connection with Plats i-A to 20-B consists of corn, 
oats, wheat, and timothy for two years. The rotation used in connec- 
tion with Plats 21 to 27 consists of corn followed by rye, vetch, and 
crimson clover as a cover crop; oats followed by soybeans and cow- 
peas 3 S a cover crop; wheat ; and timothy and clover for two years. 
The rotation used in connection with Plats 28 to 34 consists of corn 
followed by rye. vetch, and crimson clover as a cover crop; potatoes; 
ryej and timothy and (lover for two years. The rotation on Plats 
35 to p consist s of com with rye, vetch, and crimson clover as a cover 
crop; potatoes with rye as a cover crop ; tomatoes with rye, vetch, and 
crimson clover as a cover crop; lima beans with rye, vetch, and crim- 
son clover ai a cover crop; and cucumbers with rye and vetch as a 

1 J'n-cnU''] ;it the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 19, 1920. 

1 Director Oi the New Jersey Agricultural Kxperhnent Station and dean of 
I : ' olle^e of Agriculture and Mechanic Arts, New Brunswick, 



lipman: value of liming in crop rotation. 



207 



cover crop. The rotation used for Plats 42 to 48 consists of corn 
with rye, vetch, and crimson clover as a cover crop ; oats and peas fol- 
lowed by millet ; rye and vetch followed by rape ; rye followed by cow- 
peas and the latter by rye as a cover crop ; and oats and peas followed 
by cowpeas. It will be noted then that Plats 21 to 48 were employed 
for the study of four distinct rotations in which legumes have been 
included and in which the lime factor has been studied. 

Plats 21, 28. 35, and 42 have received no applications of lime. Plats 
2 5i 3 2 > 39> and 46 have received applications of magnesian limestone 
at the rate of a half ton per acre once in each 5-year rotation. Plats 
26, 33> 40, and 47 have received corresponding applications of 2,000 
pounds per acre; and Plats 27, 34, 41, and 48 have received corre- 
sponding applications of 4,000 pounds per acre. 

A comparison thus becomes possible between Plats i-A to 20-^4, 
unlimed, and the corresponding Plats i-B to 20-B, limed, used in 
connection with a rotation of nonlegumes. A comparison becomes 
possible, also, between plats receiving no lime, a half ton, 1 ton, and 
2 tons per acre in connection with four different rotations including 
leguminous crops. Xo attempt will be made to review in this paper 
the data secured for the period 1908-1912 inclusive. The data dis- 
cussed here represent the returns for the years 191 3 to 1918, inclu- 
sive. It should be added here, for the sake of completing the record, 
that Plats l-A to 20-B annually received, with few exceptions, acid 
phosphate at the rate of 640 pounds per acre and muriate of potash 
at the rate of 320 pounds per acre, in addition to the special nitrogen 
treatment. On the other hand, Plats 21 to 48, used for the legume 
rotations, received annually 300 to 400 pounds of acid phosphate, 100 
pounds of muriate of potash, and nitrogen in the form of nitrate of 
soda, ground fish, or tankage equivalent to about 15 to 30 pounds 
per acre. 

Table 1 shows the yields obtained from Plats 1 and 7, which have 
received no fertilizer at all since 1908; from Plats 4 and 19, which 
have received acid phosphate and muriate of potash only; from Plat 
6, which has received annual applications of 16 tons of horse manure 
per acre aside from the acid phosphate and muriate of potash; from 
Plat 9, which has received annually nitrate of soda at the rate of 320 
pounds per acre aside from the acid phosphate and muriate; and from 
Plat 18, which has received annual applications of horse manure, 
nitrate of soda, acid phosphate, and muriate. A comparison is given 
in each case of the corresponding limed and unlimed plats. 



208 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table i. — Yields of nitrogen in pounds per acre for the years from 1913 to 
1918 in rotations zcithout legumes. 



Plat No. 


Corn, 1913. 


Oats, 


1914. 


Wheat, 1915. 


Timothy, 1916. 




















Limed. 


Unlimed. 


Limed. 


Unlimed. 


Limed. 


Unlimed. 


Limed. 


Unlimed. 


I 


24.65 


30.84 


I 7-3 2 


IO.55 


16.68 


23-45 


14.56 


I7-5 1 


7 


45-39 


13.69 


8.70 


11.88 


18.70 


7-34 


20.24 


6-53 


4 


39.81 


23-03 


II.44 


20.54 


16.36 


23-57 


15-41 


14.84 


19 


32.13 


20.73 


14-54 


17.06 


20.94 


18.71 


I9.52 


12.30 


6 


44.84 


60.13 


24.14 


35-94 


54-25 


56.82 


34-41 


37-93 


9 


53-59 


38.72 


18.60 


28.64 


34-o6 


'45-38 


28.57 


26.19 


18 


74.10 


72.90 


35-90 


29.88 


69.10 


72.14 


37-94 


38.39 


Total 


314-51 


260.04 


130.64 


160.52 


230.09 


247-41 


170.65 


I53.69 


Plat No. 


Timothy, 1917. 


Corn, 


1918. 


Total. 


Annual 






















Limed. 


Unlimed. 


Limed. 


Unlimed. 


Limed. 


Unlimed. 


Limed. 


Onlimed. 


I 


6.62 


13-32 


47-53 


40.57 


127.36 


142.27 


21.23 


23-71 




7.28 


3-74 


43-85 


24.20 


144.16 


67.38 


24.03 


II.23 






9-54 


8.51 


49-33 


39-84 


141.89 


130.33 


23.65 


21.72 


19 


19.99 


7.41 


59-61 


38.28 


166.73 


II4.49 


27.79 


19.08 


6 


3I.36 


36.36 


70.91 


71-23 


259.91 


298.41 


43-32 


49-73 


9 


23.81 


28.29 


60.71 


54-46 


219.34 


221.68 


36.56 


36.95 


18 


46.24 


41.99 


95-23 


9I-5I 


358.51 


346.81 


59-75 


57.8o 


Total 


I44-84 


139-62 


427.17 


360.09 


I,4I7-90 


1,321.37 


236.33 


220.22 



It will be noted that the soil of Plat y-A is not as productive as that 
of Plat y-B. The average yield of nitrogen for Plat y-B has been 
24.03 pounds per acre, while the average yield of nitrogen from the 
unlimed plat J-A has been 11.23 pounds per acre. Aside from that 
the differences are slight. Even with the returns from Plats J-A 
and y-H included, the annual yield of nitrogen from the seven limed 
plats has been 3376 per acre, while the corresponding yield from the 
unlimed plats lias been 31.46 pounds per acre, or a difference of 2.30 
poimd> per acre only. The yield of nitrogen from Plat 6-B, receiv- 
ing annually 16 tons of horse manure per acre, has been 43.32 pounds, 

whereas the corresponding yield from the unlimed plat &A has been 

p.73 pounds of nitrogen per acre. I Mat iS-B has yielded 5975 
pounds "f nitrogen per acre, and I Mat iH-A 57.80 pounds of nitrogen 
per a< re. li will be noted, therefore, that with the rotation of non- 
legume afl employed, the use of 1 ton of ground limestone in [908 
and the Corresponding Use of 2 ions of ground limestone per acre in 
I913 and [918 have ihowfl no marked advantage from tbe lime. 

An entirely different picture is shown by the rotations in which 
h imes have been included, as shown in Table 2. 



lipman: value of liming in crop rotation. 



Table 2. — Yields of nitrogen in pounds per acre in rotations with legumes. 



Plat No. 


«9*3- 


1914. 


J 9'5- 


1916. 


1917. 


1918. 


Total. 


Annual 
average. 


Increase 


21 


25.61 


19.65 


24.13 


^ ^ =;o 


10 01 




t *7 1 nc 


28.84 




25 


41.16 


21.48- 


^0.47 


74 68 


27.81 


60.28 




42.64 


t "2 8n 
1 J.ou 


26 


52.28 


23.38 


29.59 


106.09 


32.26 


62.56 


306. 16 






27 


54.18 


24.02 


20.74 


OO 77 

yy- / / 


1A K() 
o4-j u 




307.10 


49-5 1 


22 67 

20^7 


28 


33.29 


22.47 


28.19 


53.89 


27.3O 


cc 01 


220. 1 5 


36.69 




32 


56.52 


21.72 


29.38 


79. 16 


^4 41 


/ - u 


278.24 


48.04 


1 1 -3^ 


33 


62.12 


21.14 


30.58 


90.80 


37-52 


60.00 


302.I6 


50.36 


13-67 


34 


60.85 


19.26 


28.47 


96.63 


34-65 


69.24 


3O9.II 


51-52 


14.83 


35 


42.98 


15.42 


40.55 


16.69 


9-50 


58.50 


183.64 


30.61 




39 


46.52 


16.41 


42.86 


19.30 


16.94 


69.9O 


211.93 


38.65 


8.06 


40 


56.28 


19.25 


46.68 


23.16 


16.94 


70.05 


232.36 


38.73 


8.12 


4i 


62.05 


16.34 


48.71 


I4-3I 


15-86 


72.92 


230.19 


38.36 


7-75 


42 


36.95 


29.94 


23-74 


52.02 


59-72 


59-40 


261.79 


43-63 




46 


39-75 


40.13 


79-32 


85.68 


104.83 


62.79 


412.50 


68.75 


25.12 


47 - 


43-02 


39-44 


109.78 


95-93 


104-92 


58.29 


45L38 


75-23 


31.60 


48 


44.78 


42.85 


116.71 


78.00 


119-38 


56.52 


458.24 


76.37 


32.74 



Here marked increases have been obtained from the use of a half 
ton of ground limestone per acre once in five years. Still more 
marked increases were secured from 1 ton of ground limestone used 
once in five years. On the other hand, the employment of 2 tons of 
magnesian ground limestone per acre instead of 1 ton has not shown 
any further marked increases in the yield of nitrogen. In Rotation 1, 
an application of 2,000 pounds of ground limestone produced an aver- 
age increase in the yield of nitrogen amounting to 22.19 pounds per 
acre. The corresponding increase in Rotation 2 was 13.67 pounds 
per acre ; in Rotation 3, 8.12 pounds per acre; and in Rotation 4, 31.60 
pounds per acre. In some instances, the yields of nitrogen per acre 
have been very high, as, for example, the yield of 1 16.71 pounds on 
Plat 48 in 1915 and 119.38 pounds in 1917. Evidently, Rotation 4 
was more effective for the accumulation of atmospheric nitrogen than 
were any of the other rotations, particularly Rotation 3. In round 
figures, the average yield of nitrogen with 1 ton of ground limestone 
per acre once in five years was 51 pounds for Rotation 1 ; 50 pounds 
for Rotation 2 ; 38 pounds for Rotation 3 ; and 75 pounds for Rota- 
tion 4. Evidently, the returns in these rotations were due in large 
measure to the fixation of atmospheric nitrogen, for the average 
annual application in nitrate of soda, tankage, or ground fish was only 
20 pounds. On the other hand, in the nonlegume rotations Plat 9-B, 
which has been receiving annually about 50 pounds of nitrogen in the 
form of nitrate of soda, has yielded only an average of 36.56 pounds 
of nitrogen. 



210 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 3. — The influence of lime on the yield of nitrogen in rotations with 
legumes, as shown by increases over unlimed plats. 





No lime. 


1,000 lbs. 


2,000 lbs. 


4,000 lbs. 




lime. 


lime. 


lime. 




34-94 


49-52 


53-84 


53-94 






14.58 


18.90 


19.00 



Table 3 shows that for the period from 19 13 to 191 8 inclusive the ■ 
increase due to the use of 1 ton of ground limestone per acre in each 
5-year period has been, approximately, 19 pounds per acre. The 
corresponding increase from applications of 4,000 pounds of ground 
limestone per acre have not been larger. 

It will be evident, therefore, that : 

1. In rotations of nonlegumes lime is not a vital factor in increas- 
ing nitrogen yields except in the case of soils well supplied with 
organic matter or so deficient in lime and other basic materials as to 
lead to textural deterioration or the formation of toxic compounds of 
aluminum and iron. 

2. With rotations of nonlegumes it is difficult and uneconomical to 
maintain an adequate supply of nitrogen in the soil. 

3. Crop rotations which include legumes show the importance of 
lime for the proper accumulation of nitrogen from the atmosphere. 
Different soils may react differently as to amounts and kinds of lime 
employed. Where the lime requirements of the land are more or 
less pronounced, the use of lime becomes an efficient factor in main- 
taining an adequate supply of nitrogen in the land. 

LIMING AS RELATED TO FARM PRACTICE. 1 

Frank D. Gardner. 2 

The art and practice of liming soils is much older than the science 
relating to the subject. The practice dates back to the time of 
Hrsinfl. r,ioo year- before the beginning of the Christian era. The 
knowledge gained during ibis long period relative to the practice of 
tuning soils lias, in the absence; of records, been banded down from 
generation 1o <'<ner;itinn by word of nx.nth and has never found its 

1 Presented at the thirteenth annual meeting of the American Society of 
noiny, Springfield, Mass., October 10, iojo. Contribution from the Penn- 
■-\\ .una Agricultural Kxpcriment Station, State College, Pa. 
Professor of agronomy, Pennsylvania State College. 



GARDNER: LIMING AS RELATED TO FARM PRACTICE. 211 

way into print. Available information of a practical nature is, there- 
fore, meager. In any event, it will be more profitable for us to dis- 
cuss the practice of today with a view to applying our present facts 
and findings as accumulated by research to the problem at hand. 
This should be the acid test and may throw some light on the status 
of our investigations as applied to the big problem of liming soils. 

As one dealing with the practice of liming, I may ask, "Do the 
experimental tests to date cover the field of inquiry? Are the results 
thus far secured conclusive? Are there other points yet to be cleared 
up?" As a business proposition, the use of lime on land is not for 
one year only or for even a few years, but should be considered 
from the standpoint of a series of years. Whether for a longer or 
shorter period, does it pay to apply lime to the soil and what evi- 
dence have we that it does pay? As a matter of common observa- 
tion, many practical farmers over a wide range of territory have 
long been in the habit of applying lime to their fields at intervals. 
It is interesting to note that the more successful farmers are num- 
bered among the regular users of lime relatively more frequently than 
the less successful ones. To be more specific, I will cite a few ref- 
erences from experiment station literature relative to the need for 
lime and the profits from lime. In Bulletin 164 of the Pennsylvania 
Agricultural Experiment Station, entitled " Lime Requirement of 
Pennsylvania Soils," the author, Prof. J. W. White, says: "There 
is no one soil condition more prevalent in the humid region and 
possibly none that has a greater controlling influence on the growth 
of crops than soil acidity." 

In Circular 36 of the Illinois Agricultural Experiment Station, 
Prof. J. E. Readhimer says : " To the lack of limestone in the soil 
is probably attributed more failures with clover than to any other 
soil condition." In the southern part of Illinois, clover is generally 
a failure until the soil has received a rather liberal application of 
lime, after which good stands of clover may be expected nine times 
out of ten. 

In Circular 54 from New Jersey is reported the value of the in- 
crease in crop yields for four crop rotations as influenced by mag- 
nesian limestone and nonmagnesian limestone. The rotations each 
extended over five years and received an initial application of 2 
tons per acre of ground limestone of the kinds above mentioned. 
At that time, the cost of such ground limestone was $2.50 per ton. 
The value of increase for each rotation and for each kind of lime- 
stone is as follows : 



212 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Rotation. 



Magnesian limestone. Non-magnesian 
limestone. 



Xo. i, General farm crops 

Xo. 2, General farm crops and potatoes 

Xo. 3. Market garden crops 

Xo. 4, Forage crops 



$34-75 $23-93 
21.22 16.50 
35-48 a 60.86 
23-25 31-13 



a Diseased. 



WHEN IS LIME NEEDED? 



Lime serves several purposes in the soil, but we will here consider 
only those relating" to soil acidity. The symptoms of soil acidity are 
manifest to those having studied the subject, first by the character 
and condition of vegetation. These symptoms are afterwards veri- 
fied by different tests. The vegetative indications vary with different 
sections of the country, depending upon the natural flora of the 
locality. In all cases, however, the partial or complete failure of 
those crops common to the locality most sensitive to soil acidity and 
the encroachment on the land of acid-tolerant species of weeds and 
grasses are the first symptoms of soil acidity. The most common 
test to verify the' suspicion is that made with neutral blue litmus 
paper. There are a number of quantitative tests familiar to all of 
you. Several are in use at different experiment stations and yet no 
two will give comparable results. 

In Pennsylvania, especially on the limestone soils, the first symp- 
toms of soil acidity are the failure of common red clover and the 
occurrence of sorrel (Rumex ace to sella') . In the DeKalb region of 
the State the wild daisy, yellow trefoil, poverty grass, and dew- 
berries are also indicators of soil acidity, while in the glaciated 
regions, paintbrush is the most common weed on acid soils. 

In Xcw York, Ikirker reports that indications of the need of 
lime arc the prevalence of sorrel and paintbrush, the failure of red 
clover, and the turning of bine litmus paper red when brought in 
contact with the moist soil. 

In Iowa. Stevenson reports horsetail rush, sheep sorrel, corn 
spnrry. and wood horsetail as weeds indicating soil acidity. Acidity 
may also be suspected wherever red clover, sweet clover, and alfalfa 
will not make satisfactory growth. 

Fortunately, our common farm and garden crops manifest a wide 

range in their tolerance for soil acidity. This makes possible crop 
rotations with acid-resistant crops on extremely acid soils far re- 
moved from sources of lime supplies. It is interesting to note that 
in general those crops most sensitive to acidity arc the ones that 
USttally remove from the soil the largest amount of lime and mag- 
The < rop mosl sensitive to acidity and at the same time most 



GARDNER: LIMING AS RELATED TO FARM PRACTICE. 



213 



responsive to applications of lime are alfalfa., red clover, Canada 
pea, garden pea., soybean, cowpea, lettuce, beet, cabbage, cauliflower, 
celery, spinach, onion, pepper, cantaloup, and barley. Those less 
dependent on lime and more tolerant of acidity are the Irish potato, 
sweet potato, carrot, watermelon, blackberry, strawberry, buck- 
wheat, rye, corn, redtop. cotton, tobacco, peanuts, Japan clover, and 
garden beans. 3 

EXTENT TO WHICH LIME IS NEEDED. 

I believe that all of the experiment stations in the States north 
of those bordering on the Gulf and east of the Mississippi River 
have issued circulars or bulletins relating to the use of lime on land. 
A number of these experiment stations have made estimates or 
actual surveys to determine the percentage of agricultural lands 
actually in need of lime. Bulletin 164 from the Pennsylvania station 
. reports results of 1474 lime requirement determinations on as many 
samples collected from 50 counties in the State. It found 72 per- 
cent of the soils tested in need of lime. These samples were taken 
from soils that had, in many cases, recently been limed, as well as 
from fields that never had been limed or that had received lime at 
some rather remote period. In Xew York State Station Bulletin 
430, Barker reports that three-fourths or more of the soils of Xew 
York would be benefited by liming. These soils call for lime at the 
rate of from 1 ton to 10 tons of limestone per acre as determined 
by actual tests. Just what are the corresponding amounts of lime- 
stone most profitable to use is another question. In Xew Jersey 
Extension Circular No. 7, Dickey says 80 to 90 percent of the soils 
of New Jersey need lime. In Iowa Circular Xo. 58, Stevenson re- 
ports that 60 percent of the soils of that State are acid and need 
lime. Miller, in Missouri Station Bulletin 146. says two-thirds of 
the soils in that State need lime from insignificant amounts to as 
much as 5 or 6 tons of limestone per acre. One-fourth of them need 
2 tons of limestone or more per acre. From Florida, we have the 
report that two-thirds of the soils in that State are acid. This esti- 
mate is from an examination of 189 samples collected from 17 
counties. From these statements, it is evident that the need of lime 
on land is very general thruout the humid region of the United 
States. 

3 See Tenn. Agr. Expt. Bui. 96, p. 20. 

/ 



214 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



CAUSES OF SOIL ACIDITY. 

There are many factors that contribute to soil acidity and it 
is quite certain that our knowledge on this point is as yet incom- 
plete. I will, therefore, mention only a few of the principal causes 
such as : 

1. The loss of lime from the soil by leaching. 

2. The removal of lime in farm crops. 

3. The addition of acid to the soil in certain fertilizers. 

4. The formation of acids thru the decomposition of crop residues 
and organic manures. 

5. The contamination of soils by gases and fumes from coke 
ovens, smelters, factories, etc. 

OTHER IMPORTANT REASONS FOR LIMING. 

In addition to correcting possible soil acidity, attention may be 
called to the harmful effects of certain inorganic compounds in the 
soil, notably soluble salts of aluminum, which are precipitated, or 
at least rendered nontoxic, by liming. Also, there are good reasons 
for believing that long cultivated lands are rather frequently so poor 
in lime as not to be able to supply the physiological needs of crops 
with high lime requirements such as clpver and alfalfa. 

ESTIMATED RATE OF LOSS OF LIME. 

At the Rothamsted Experiment Station in England, lysimeter 
experiments show that 20 pounds of lime carbonate per acre may be 
leached from the soil in each inch of drainage water. With 15 
inches of drainage water, about the average there, the annual loss 
would be 300 pounds of carbonate of lime per acre. On chalked 
lands, having as much as 3 percent of carbonate of lime, this loss 
will reach 1. 000 pounds of carbonate of lime annually. 

E. Van Alstine reports results of lysimeter experiments by Hana- 
mann ill which soils rich in lime lost as much as 2,700 to 3,500 pounds 
per acre of carbonate in one year. T Tall and Miller recorded a loss 
of 700 to 800 pounds of carbonate of lime in one year without 
ammonium alt and 1.200 pounds per year with ammonium salts. 

in [llinoifi Bulletin 212, Stewart reports that Hopkins calculated 
for tli' "i.-iv ill loam on ti^ht clay, 760 pounds carbonate of lime per 
BCfC remOTed annually from 20 inches of soil and 542 pounds under 
the rune < < .] 1' 1 it ions from the Odin experimental field. 

I* : al once evident 1 1 in I the rate of removal depends on several 
UCh as the amount of lime in the soil, the annual rainfall, 



GARDNER: LIMING AS RELATED TO FARM PRACTICE. 



215 



the extent of percolation, the rate of acid formation, and the por- 
osity of the soil. 

These facts, together with our knowledge of the large amount 
of lime found in drainage water generally, supports the conclusion 
that lime is leached from the soil slowly but constantly until the 
point is reached where the supply of alkaline bases is insufficient to 
neutralize the accumulation of acids caused by modern methods in 
agriculture. Also the supply of lime may become so low as either 
not to meet the physiological needs of certain crops, or to prevent 
the solution of toxic inorganic soil constituents. 

GROWTH OF THE AGRICULTURAL LIME INDUSTRY. 

In the United States, the development of the agricultural lime 
industry has been very rapid in the last twelve or fifteen years and 
has extended into new territory where previous to fifteen years ago 
the liming of soils had never beeen practiced. 

Barker, in 191 7, stated that five years earlier there was only one 
company in New York State producing ground limestone for the 
agricultural trade. In 1917, there were 56 plants operating with 
a capacity of 675,000 tons annually. This output was based on oper- 
ating eight months of the year from eight to ten hours daily. 

In Volume 1, No. 5, of the Agricultural Lime News Bulletin 
the geographical production of agricultural lime in the United States 
is presented. It is shown that while the production in such States 
as Pennsylvania, Illinois, Michigan, and Ohio is large in the aggre- 
gate, the amount produced in proportion to the improved farm land 
of those States is very small and ranges from less than 10 pounds 
per acre of calcium oxid in Ohio to only 40 pounds per acre in Penn- 
sylvania. It \s stated that the states producing lime average a pro- 
duction of only 1 1 pounds each per acre and that the needs for lime 
are approximately 20 times that amount annually. 

RATE OF APPLYING LIME. 

While it is logical and may be a good practice to apply lime in 
sufficient quantities to meet fully the lime requirement of the soil 
and maintain, as far as possible, a neutral soil, such advice is not 
warranted under all conditions. Recent lime surveys show very 
large lime requirements over extensive areas. Farmers in those 
regions cannot afford to apply lime to their land in such large 



216 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



quantities, as the expense is too great. It therefore becomes a prob- 
lem of the minimum quantity that may bring profitable returns on 
the investment in lime. As yet, there are not sufficient experimental 
data covering this point to make possible a definite statement. 
Further knowledge relative to the character of acidity and its effect 
upon different crops is needed in this connection. 

Blair, in New Jersey Circular 54, says, " One-half ton of burnt 
lime or one ton of limestone is often sufficient. On soil not of lime- 
stone origin and not limed in five years, 1,500 to 2,000 pounds per 
acre of burnt lime for general farm crops is a moderate application. 
On sands and sandy loams, this may be reduced to 1,000 or 1,500 
pounds." The more organic matter there is in the soil, the more 
lime may be applied. In a rotation in which potatoes occur he 
advises liming after the potato crop sufficient only to bring clover, 
On low wet lands and mucks 5,000 to 10,000 pounds are sometimes 
needed. 

Stewart in Illinois Bulletin 212 advises for southern Illinois 1 ton 
of limestone once in three or four years. After the initial acidity 
has been destroyed, he believes this amount sufficient to keep the soil 
alkaline or sweet. 

In Pennsylvania Bulletin 164, White found the average lime re- 
quirement on the limed soils of the State to be 1,749 pounds per 
acre, while the lime requirement of the unlimed soils averaged 3,105 
pounds. In Potter County in the glaciated region 100 percent of 
the soils were acid and the average lime requirement was 7,928 
pounds, while in Lehigh County only 3 percent of the soils were acid 
and the average lime requirement was only 124 pounds. 

MOVEMENT OF LIME IN THE SOIL. 

The lateral movement of lime in well drained soils is very small. 
Thi- 1- evident from the wide range in lime requirement often found 
within ver\ short distances. On the experimental plats at the Penn- 
sylvania Agricultural Experiment Station, White reports good clover 
and alkaline soil on a spol Oil an ammonium sulfate treated plat and 
IK) clover and a very acid soil [8 inches from this spot. 

In \vell-drain<d -oils, the vertical movement of soil moisture by 
gravity and by capillary rise is usually greater than the lateral 
movement and it seems probable, therefore, that the vertical move- 
ment of lime in soils is gem-rally greater than the lateral movement. 
In spite of this, the vertical movement of lime is very slow as shown 



GARDNER: LIMING AS RELATED TO FARM PRACTICE. 



217 



by lime determinations at different depths in soils that have had 
lime applied at the surface for a long period. 

METHODS OF APPLYING LIME. 

To be effective, lime should be as thoroly mixed as possible with 
the plowed portion of the soil. This is usually most economically 
done by broadcasting lime on newly plowed land and mixing it with 
the soil by the disking and harrowing necessary to prepare the seed 
bed. Most of us adivse against plowing lime down. In theory, a 
portion of the lime application might be made before plowing and 
disked into the soil and the remainder applied after plowing as above 
suggested. There is no evidence, however, showing that this would 
be economical. The time of application or the season of the year is 
immaterial and in farm practice it will often be determined by the 
distribution of farm labor. The place in the crop rotation should be 
just preceding the crop most responsive to lime, providing it is con- 
venient to apply at that time and the preparation of the land will 
provide for proper mixing of the lime with the soil. Where this is 
not possible, it may be applied for a crop earlier in the crop rotation. 

While top dressing with lime is not generally advised, it may be 
justified on land already seeded to clover, especially when the suc- 
cess of the clover will be largely determined by the lime. For top 
dressing, I believe that finely pulverized limestone may be better 
than freshly burned lime in spite of frequent statements to the 
contrary. Freshly burned lime used as a top dressing is subject 
to puddling, in which case the lime will cake and remain on the 
surface for a long time. 

The old method of spreading lime from small piles distributed 
over the field by means of shovels is not to be recommended. Such 
distribution is too uneven to expect the best returns from it. Noth- 
ing is better for spreading lime than a lime spreader made for the 
purpose. One which will provide for a wide range in the rate of 
application, will not clog, and will spread uniformly, is to be recom- 
mended. The lime should be so placed in the field that it will be 
accessible to the lime spreader and provide for the minimum amount 
of handling of the lime. 

A lime spreader that can be conveniently attached to the rear of 
a wagon so that the lime may be transferred from the wagon to 
the spreader as it passes across the field saves much labor in handling 
the lime. Professor C. A. Mooers of the Tennessee Agricultural 



21 8 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

Experiment Station reports that the Holden distributor meets such 
requirements. It is an end-gate distributor which he reports gives 
excellent satisfaction. 

PURCHASING LIME. 

Lime should be purchased from the nearest source of supply, so 
far as quality, conditions, and prices will justify. Freight charges 
and cost of cartage are relatively large proportions of the final cost in 
such bulky, heavy material. Where purchased at a distance, carload 
lots are advised. This will frequently necessitate cooperation on 
the part of purchasers. The final basis for determining the cheapest 
source of lime is to calculate the cost per unit of active material of 
the different forms and qualities available, laid down on the land of 
the farmer. Magnesian limestone has thus far not been objected 
to on the part of the farmers. Limestone containing more than 10 
percent of magnesium carbonate is called magnesian limestone. As 
the percentage approaches 45 percent, it is then called dolomite. 
Magnesium is found in all soils and is an essential element to plant 
growth. It has a higher neutralizing power than calcium, the exact 
ratio of calcium oxid and magnesium oxid being 100 to 140. The 
magnesium oxid content of lime may, therefore, be multiplied by 
1.4 to obtain its relative neutralizing power as compared to calcium 
oxid. The product should then be added to the calcium oxid content 
of the lime in question. 

Table 1 shows the composition and value of certain forms of 
lime in Pennsylvania. 



Table i. — Composition, retail price and unit value of pulverized limestone and 
burnt lime from 1917 to 1919, as determined by the Pennsylvania 
Department of Agriculture. 



Year. 


Material. 


No. of 
samples. 


CaO. 


MgO. 


Retail 
price per 
ton. 


Lbs. CaO 
for $1.00. 


Cost per 
unit, 
cents. 








Percent. 


Percent. 








1917. 


Limestone 


21 


44-35 


4.58 


$4-6 1 


216 


9.6 




Burnt lime 


10 


63.07 


2.50 


6.00 


220 


9.0 


1918. . 


Limestone 


29 


46.3 ' 


4-32 


7-39 


139 


14.4 




Hurnt lime 


6 


66.08 


9.00 


7-43 


207 


9-7 




Limestone 


56 


49-94 


1.80 


7.29 


143 


14.0 




Bumf lime 


13 


69.42 


2.44 


9.60 


151 


13-3 



GARDNER : 



LIMING AS RELATED TO FARM PRACTICE. 



219 



White, in Pennsylvania Station Bulletin 149, says: 

The increased cost of the very finely ground limestone, together with the 
rapidity with which it disappears from the soil as compared with coarser 
material, leads to the conclusion that an application of material all of which 
will pass a 10 mesh screen and include all of the fine material incident to such 
grinding is sufficiently fine for soil improvement if applied somewhat in excess 
of the immediate need of the soil. 

He also presents results of pot experiments with four grades ot 
limestone particles for both high calcium and magnesium limestone 
compared with equivalent amounts of burnt lime and gives refer- 
ences to other experiments with the fineness of ground limestone. 

FINENESS OF GROUND LIMESTONE. 

The fineness of pulverized raw limestone is a subject on which 
there is much disagreement. There are not yet sufficient experi- 
mental data and accumulation of facts concerning cost of pulver- 
ization to arrive at a definite conclusion. Material finer than 60/100 
to 80/100 of an inch in diameter is known to be immediately avail- 
able. Material coarser than 1/50 of an inch in diameter requires 
some time to become available. At present, a number of the experi- 
ment stations are advising the use of the total product of pulveri- 
zation that will pass a 10-mesh screen, thus providing for no lime- 
stone particles larger than 1/10 of an inch in diameter. In such a 
product 50 percent or more of the total will usually pass the 60-mesh 
screen. 

Barker, in Bulletin 430 of the New York State station, states that 
pulverization as fine as cement may add $0.50 to $1.50 per ton to the 
cost. It also necessitates the use of bags, entailing an additional 
cost of $1.00 per ton or more. Such fine material is more difficult 
and more disagreeable to handle than when not quite so fine. 

Stewart, of the Illinois station, after four years' results on Newton 
Experimental Field, found evidence that finely ground limestone 
was no more effective than the total product from a one-fourth- 
inch screen which contained both finer material for immediate use 
and coarser material for durability. 

HOME BURNING AND GRINDING. 

Where limestone is available on the farm or in the immediate 
locality, the home burning of limestone should be encouraged where 
the supply of labor and cheap available fuel is at hand. In the 
absence of fuel, the pulverization of such stone with portable pul- 



220 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



verizing machinery should be considered. Work of burning or 
pulverizing limestone can generally be done at times when farm 
work is not pressing. The prevalence of farm tractors, together 
with the various makes of portable pulverizers now on the market, 
make such home production of agricultural lime feasible and prof- 
itable. 

LIME NOT A FERTILIZER. 

In conclusion let us not forget the old adge that " Lime and lime 
without manure makes both farm and farmer poor." Lime should 
be used to correct soil acidity and meet the lime requirement of 
soil and plants. It can not be expected to take the place of the 
essential plant food constituents so frequently needed in the soil. 
After liming, use manure and fertilizers in the usual way, keeping 
in mind the fact that the returns from these will be greatest where 
sufficient lime is used. 

A COMPARISON OF MAGNESIAN AND NONMAGNESIAN 
LIMESTONES. 1 

A. W. Blair. 2 

Frequent requests for information with reference to the relative 
value of magnesian and nonmagnesian limestones led to the laying 
out, in 1908, of four blocks of plats, each block containing 7 twentieth- 
acre plats, to be devoted to this work. The plan provides for four 
different 5-year crop rotations in which the two forms of lime are 
used. The following rotations were adopted: 



Rota- 
tion. 


First year. 


Second yeir. 


Third year. 


Fou'tfa year. 


Fifth year. 


f 


( orn. 


Oats. 


Wheat. 


Timothy and 


Timothy awl 










clover. 


clover. 




( orn. 


Potatoes. 


Rye. 


Timothy and 


Timothy and 










clover. 


clover. 




( urn. 


I'olatoe*. 


Tomatoes. 


Lima beans. 


Cucumbers. 




' (orn. 


' awl peas, 


Kye awl vetch, 


Rye, cowpcas. 


Oats and peas, 






millet 


rape. 




cowpeas. 



M.t.d at the thirteenth annual meeting of the American Society of 
Agronomy, Springfield, Mass., October 19, 1920. 

['rot* '-or ,,i agricultural chemistry, Rutgers College and the State Univer- 
sity of New Jersey, New Urunswick, N*. J. 



BLAIR : COMPARISON OF LIMESTONES. 



221 



Thruout the entire period the nonlegume crops have been followed 
by legume cover crops wherever this has been possible. The plats 
were so arranged that in each of the four blocks there was a check 
plat (no limestone) and three plats which received a half ton, i ton, 
and 2 tons of calcium limestone per acre, and three which received the 
same quantities of magnesian limestone. The limestone was finely 
ground, being the so-called 200-mesh limestone. The first applica- 
tion was made before planting the corn in 1908 and subsequent appli- 
cations were made preceding the corn in 191 3 and again in 1918. 

The soil is a loam or gravelly loam which originally had a lime re- 
quirements of about 1,200 to 1,800 pounds per acre. 

It has been customary to apply to these plats annually about 300 to 
400 pounds of acid phosphate, 100 pounds of muriate of potash, and 
a nitrogenous fertilizer equivalent to 160 to 200 pounds of nitrate of 
soda pef acre. There have been slight variations in the fertilizer 
treatment for the different rotations, but the treatment for the seven 
plats in a given rotation and for a given crop has always been uniform. 

Thruout the entire period a careful record has been kept of the 
crop yields, and with the exception of two crops, tomatoes and cucum- 
bers in rotation No. 3, a complete record has also been kept of the 
amount of nitrogen recovered in the various crops. 

On account of the varied character of the crops and the fact that 
some were harvested in the ripened state and saved as grain and 
straw, others as forage crops, and still others like potatoes and toma- 
toes were weighed as harvested, it is difficult to make a comparison 
of yields without introducing lengthy tables which are not easily ex- 
hibited and explained in a paper of this character. 

For this reason it has seemed best to compare the two treatments 
by means of the total nitrogen recovered in the crops. The amount 
of nitrogen thus recovered is calculated by multiplying the weight of 
the crop — dry or field weight according to the method of saving — by 
the percentage of nitrogen in a sample of the crop, the nitrogen deter- 
mination being made on a sample comparable to the crop as weighed. 
With abnormal nitrogen treatment it would be possible so to change 
the nitrogen content of the plant as to make this method of compari- 
son unfair, but in this experiment the nitrogen treatment was normal 
and uniform thruout and all the plats yielded normal crops. 

The nitrogen yields reported as 5-year averages, 1908-1912 and 
191 3-19 1 7, inclusive, for the four rotations are shown in Table I. It 
should be explained that the low yields for rotation 3 in the first por- 
tion of the table are due to the fact that the nitrogen was not calcu- 
lated for the tomato crop o'f 1910 and the cucumber crop of 1912. 



2 22 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table i. — Total pounds per acre of nitrogen recovered thru the crops of a 

5-year rotation. 



FIRST PERIOD, IOX)8-I9I2. 



Rotation 
No. 


Check 'no 
limestone). 


0.5 ton 
calcium 
imestone. 


0.5 ton 
magnesian 
limestone. 


1.0 ton 
calcium 
limestone. 


1 ton 
magnesian 
limestone. 


.2 tons 
calcium 
limestone. 


2 tons 
magnesian 
limestone. 


I 


129.9 


135-4 


185.2 


I52.0 


184.9 


162. 1 


193-7 


2 


140.6 


182.3 


169.4 


156.O 


167-3 


178.6 


174-3 


3 


63.4 


75-8 


71.9 


75-9 


8l.O 


79-6 


80.9 


4 


3I3-I 


3840 


395-5 


442.0 


424.2 


433-1 


424-5 


Average. . . 


161. 8 


194.4 


205.5 


206.5 


214.4 


213.4 


218.4 



SECOND PERIOD, I913-I917. 



I 


124.8 


173-2 


195-6 


213.4 


243-5 


226.1 


242.3 


2 


165. 1 


192.3 


221.2 


233-3 


242.2 


257-4 


239-9 


3 


125. 1 


150.6 


142.0 


167.2 


162.3 


157-0 • 


157-3 


4 


202.4 


275-1 


349-7 


339-4 


393-1 


416.5 


401.7 


Average. . . 


154-4 


197-8 


227.1 


238.3 


260.3 


264.2 


260.3 



On examining the first section of Table i, it is found that the aver- 
age for the four rotations shows a slight advantage in favor of the 



magnesian limestone as follows: 

Pounds of nitrogen recovered 
per acre (5 year rotation). 

f calcium limestone 194-4 

0.5 ton per acre i . 
J I magnesian limestone 205.5 

f calcium limestone 206.5 

1.0 ton per acre i .. . t t 

{ magnesian limestone 214.4 

("calcium limestone 213.4 

2.0 tons per acre i . „ tQ . 

1 [ magnesian limestone 218.4 

It mtis1 be admitted ill this connection that the differences in favor of 
the magnesian limestone are small and .also that in some of the indi- 
vidual rotations the figures are reversed. 

Attention may he called to the high yields of nitrogen in rotation 4. 
This 18 due in pari t<> tlie fact that two crops were harvested from these 
plats during four of the five w ars, and in part to the fact that legume 
were frequently grown in this rotation. It is of further interest 
to DOte thai the average yield of nitrogen for this rotation was, with- 
out exception, more than double the average yield for rotations I 
and 2. 



BLAIR : COMPARISON OF LIMESTONES. 



223 



With the exception of the potatoes and tomatoes, the limestone- 
treated plats, even where the application was only a half ton per acre, 
have yielded more nitrogen than the check plats. This increase in 
nitrogen is due in part to a higher percentage of nitrogen in the crops 
from the treated plats and in part to increased yields. It is believed 
that the higher percentage of nitrogen in the legume crops from the 
treated plots can be explained on the ground that liming makes the 
conditions favorable for the nodule- forming organisms and that with 
increased nodule formation more nitrogen is stored up in the plant. 

The results for the second 5-year period, 1913 to 1917, are given in 
the second section of Table 1. An examination of the averages for 
the four rotations shows that for the ^2 -ton and i-ton applications the 
magnesian limestone gave slightly larger yields of nitrogen than the 
calcium limestone. For the 2-ton application the results are slightly 
in favor of the calcium limestone. 

The corn crop of 1918 begins the third 5-year period, which has not 
yet been completed. The figures for this crop (Table 2) are of in- 
terest in connection with those already reported. 



Table 2. — Total nitrogen recovered in the corn crop of 1918 (pounds per acre). 



Rotation 
No. 


Check. 


0.5 ton cal- 
cium lime- 
stone. 


0.5 ton mag- 
nesium 
limestone. 


1.0 ton cal- 
cium lime- 
stone 


1.0 ton mag- 
nesium 
limestone. 


2 tons cal- 
cium lime- 
stone. 


2.0 tons 
magnesium 
limestone. 


I 


48.3 


54-8 


60.3 


58.5 


62.6 


57-7 


54-8 


2 


55-0 


52.3 


67.O 


63.7 


60.O 


67-3 


69-3 


3 


58.5 


68.7 


69.9 


72.0 


70.0 


72.0 


72.9 


4 


59-4 


6l.6 


63.O 


56.6 


58.3 


66.7 


56.5 


Average. . . 


55-3 


59-3 


65.O 


62.7 


62.7 


65-9 


63-4 



Again taking the averages for the four rotations, it will be noted 
that with the Yi -ton application the magnesian limestone gave a re- 
turn of 65 pounds of nitrogen per acre as against 59.3 pounds for the 
calcium limestone. With the i-ton application the average yields 
are the same for the two forms of limestone, and with the 2-ton appli- 
cation the calcium limestone yielded 2^ pounds of nitrogen per acre 
more than the magnesian limestone. 

It will thus be observed that the results with the two forms of lime- 
stone are very nearly the same whether we compare them by 5-year 
periods or by the results of a single crop. 

Three crops of tomatoes have now been grown on these plats and it 
is of interest to compare the yields with reference to amount and form 
of limestone used. These comparisons are shown in Table 3. 



224 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



It is noteworthy that with the calcium limestone the yields invari- 
ably decrease as the application increases from y 2 to 2 tons per acre, 
altho for two out of the three years all of these lime-treated plats 
show an increase over the check plat. For the third year the check 
plat gave the highest yield of any. 

The yields from the magnesian limestone plats are fairly uniform 
and do not show any particular tendency either to increase or decrease 
with increase of limestone. They exceed the yields on the check plats 
for two out of three years. When the averages are compared, it is 
found that the yields for two of the three years are practically the 
same for the calcium as for the magnesian limestone. For the third 
year the magnesian limestone yielded 4.00 pounds per acre more than 
the calcium limestone. 



Table 3. — Field weight of marketable tomatoes with different amounts of 
calcium and magnesian limestone (pounds per acre). 



Treatment. 


Yield, pounds per acre. 
1910. 1915- 1920. 


Check 


7,720 


24,080 


18,728 


0.5 ton calcium limestone 


13.240 


28,550 


I5.034 


1.0 ton calcium limestone 


11,240 


27,860 


13.768 


2.0 ton calcium limestone 


9,960 


25,6lO 


9.879 


Average 


II,480 


27,340 


12,894 


0.5 ton magnesian limestone 


11,540 


25.454 


16,664 


1.0 ton magnesian limestone 


13,000 


27,720 


17.747 




9,620 


28,924 


16,352 




11,387 


27»366 


16,921 



Lime requirement determinations were made on samples of soil 
from all plats in [913, 1917, and 1919. In most cases the check plats 
showed a requirement of about 1,200 to 1,600 pounds of lime (CaO) 
per acre. 

In [919, aboul a year after the third application of lime, the plats 
thai received a half ton of calcium limestone per acre showed an aver- 
age lime requirement of about 675 pounds per acre; the average re- 
quirement for the corresponding magnesian limestone plats was 600 
pounds per acre. The average requirement for the plats receiving I 
inn of calcium limestone per acre was 250 pounds and for the corre- 
sponding magnesian limestone plats 200 pounds per acre. All plats, 
both calcium' and magnesium treated, which received the 2-ton appli- 
cation, were alkaline. It would thus appear that in the matter of 
satisfying lime requirement there is but slight difference between the 
two materials. 



BLAIR : COMPARISON OF LIMESTONES. 



225 



Also, in 1919, determinations were made of the hydrogen-ion con- 
centration of the same samples used in making the lime requirement 
determinations. The results, expressed as pH values, are shown in 
Table 4. 



Table 4. — Hydrogen-ion concentration, expressed as pH values, of soil from 
the calcium and magnesian limestone plats. 



Treatment. 


Rotat'on 


Rotation 2. 


Rotation 3. 


Rota'ion 4. 


Check 


5-4 


5-8 


5-5 


5-4 


0.5 ton calcium limestone 


6.1 


6.0 


6.1 


6.0 


1.0 ton calcium limestone 


6.7 


6-5 


6-3 


6.3 




7.2 


7-i 


7-i 


7.1 • 


0.5 ton magnesian limestone 


6.0 


6.3 


6.2 


6.2 


1.0 ton magnesian limestone 


6-5 


6.7 


6-5 


6.4 


2.0 ton magnesian limestone 


7.0 


6.9 


6.9 


6.9 



These figures also indicate that the difference in neutralizing power 
of the two forms of lime is slight. It must be borne in mind, how- 
ever, that these figures do not measure the lime requirement of the 
soil, but only the hydrogen-ion concentration. 



SUMMARY. 

1. The results of n years of work with the two forms of limestone 
on four different crop rotations are reported. 

2. Using the total amount of nitrogen returned in the crops as a 
measure, the two forms of limestone give results which are very 
nearly the same. The magnesian limestone appears to have a slight 
advantage. 

3. Measured by the hydrogen-ion concentration and by determina- 
tions of lime requirement of samples of the treated soil, the two lime- 
stones also have about the same corrective power. 

4. There is no indication of any toxic effect due to the use of the 
magnesian limestone. 



226 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



SULFUR SUPPLIED TO THE SOIL IN RAINWATER. 1 

B. D. Wilson. 2 

Some differences of opinion exist concerning the advisability or 
necessity of applying sulfur to soils in order to increase their pro- 
ductiveness. Data have been presented by investigators showing both 
beneficial and detrimental effects on the growth of certain plants from 
its application in one form or another. Whether the stimulative or 
depressive action, as the case may be, is a direct or an indirect one, 
or both, is more or less a matter of conjecture at the present time. 
In considering the relation of sulfur to soils, whether it be from the 
standpoint of sulfur conservation or from the effects that this con- 
stituent may have on bacterial or higher plant activity, the quantity 
of sulfur supplied to the soil in the rainwater must be taken into 
account. This fact has been recognized by a number of workers and 
analyses of the rain falling in many parts of the world have been 
made to determine its sulfur content. At Ithaca, where the rain- 
water has been analyzed for a number of years for certain con- 
stituents, sulfur lias been determined for two years, the results of 
which are herein reported. 

Miller 8 found the rain falling at Rothamsted, England, to contain 
a yearly average of 17.41 pounds of sulfur (S0 8 ) to the acre. He 
report- Gray, working at Lincoln, New Zealand, and Sestini at Ca- 
t in ia, Sicily, to have found 14.04 and 20.89 pounds, respectively. 

At Leeds, England, Crowther and Ruston (1) report the atmos- 
pheric precipitation to be extremely high in sulfur. The rain falling 
at eleven stations for a period of one year in and near the city con- 
tained, on an average. 161.27 pounds SC) a calculated to the acre basis. 
At one station near the industrial area of the city the sulfur content 
Wat a- Iml'Ii as pounds. While most of the sulfur was present 
in the form of sulfate, appreciable amounts of sulfur dioxid and 
hydrogen sulfid were always found. At (iarforlh, 6 miles east of 
l.ced . tin 1 -anie authors report the annual precipitation of sulfur 

1 ntribution from the I )cpartmen1 of Soil Technology of the New York 
■ •■ 1 ..II'-.-. "i Agriculture at Cornell I'ni vcrsity. Received for publication 
January 24. 1021. 

2 Assistant prot'< - or of soil technology, New York State College of Agri- 
culture, Cornell University, Ithaca, N. Y. 

i <:,<< is to "Literature cited," p. 229. 



WILSON : SULFUR SUPPLIED TO SOIL IN RAINWATER. 227 



(SO s ) to be equivalent to 95.68 pounds per acre, about 26 percent of 
which was found to be present in forms less highly oxidized than 
sulfates. 

Vityn (6) states from analyses of rain collected at eight different 
places in Russia that the rainwater supplied the soil with considerably 
more sulfur than was contained in relatively high yields of grain and 
straw. 

Approximately eight months' rain at Mt. Vernon, Iowa, is reported 
by Peck (3) to contain 8.44 pounds of sulfur (SO a ), while Triesch- 
mann (5) found the rain falling for a slightly longer period at the 
same place to contain 1.51 pounds. 

Stewart (4) finds the rainfall of Urbana, 111., to supply an acre of 
soil annually with an average of 45.1 pounds of sulfur. It is re- 
ported from observations extending over a period of seven years that 
the quantity of sulfur brought down in the rainwater depends directly 
on the amount of precipitation. 

The rainwater at Ithaca is collected in a metal rain gauge, which 
is emptied after each rain or snow, and the water stored until analyzed 
in glass bottles containing a few drops of mercuric chlorid solution. 
The gauge is 8 inches in diameter and stands about 9 feet above the 
ground. As the gauge is locatec in a field near which there are no 
factories, and as it is protected from birds by a movable frame 
extending a little above and beyond the top of the gauge, the water 
collected is comparatively free from contamination. 

The quantity of sulfur found in the rainwater for each of two 
years is shown in Table 1. It may be seen from this table that the 
rainfall for the two years reported supplied the soil with an average 
amount of sulfur equivalent to 26.19 pounds per acre, and that the 
values for the two years do not differ greatly. 



Table i. — Sulfur in the rainwater at Ithaca, N. Y '., between May 1, 1918, and 

May 1, 1920. 



Period collected. 


Rainfall, 


Sulfur, 


Sulfur, 




inches. 


p. p.m. 


pounds per acre. 


1918-1919 


30.27 


4.06 


27.80 


1919-1920 


24.03 


4-52 


24.58 


Average 


27.15 


4.29 


26.19 



The quantity of sulfur reported to be present in the rain falling at 
each of the several places which have been mentioned is listed in 
Table 2. An inspection of this table shows that the rainwater col- 



228 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



lected in the industrial area of England in which Leeds and Garforth 
are located is highly charged with sulfur-bearing compounds and that 
a wide variation exists in the amount of this constituent in the rain 
falling in agricultural regions. It is somewhat striking that the rain- 
water at Urbana, where there are few factories and which is situated 
in a State given over very largely to agricultural pursuits, should con- 
tain more sulfur than the amount reported to be present in the atmos- 
pheric precipitation at Garforth. The supposition has been, and it is 
perhaps generally true, that the rain falling in industrial centers con- 
tains more sulfur than that falling elsewhere. From the figures 
presented such an assumption may be very misleading, as the quantity 
of sulfur brought down in the atmospheric precipitation is sometimes 
larger in agricultural areas than in manufacturing ones. The pres- 
ence of the relatively large amount of sulfur found in the rainwater 
at Urbana can probably be accounted for from sources of atmospheric 
contamination common to most communities, such as the gases evolved 
from the use of coal by railroads and by heating and electrical power 
plants. 

Table 2. — Quantity of sulfur in the rainwater at places mentioned herein. 



Place. 



Period 
collected. 



Average 
annual 
rainfall. 



Pounds per 
acre reported 
yearly. 



Pounds per 
acre as ele- 
mental sulfur. 



Rothamsted, England (2) . 

Catania, Sicily (2) 

Lincoln, New Zealand (2) 
Garforth, England (1) . . . 



1881-87 
1888-80 
1884-88 
I9o6-'oq 

I^eds, England (1) I907-'o8 



Mt. Vernon, Iowa (3) 
Mt. Vernon, Iowa (5) 

Urbana. 111. (4) 

Ithaca. X. Y 



1916- 17 
ioi8-'io 
1913-19 

IOl8-'20 



29-95 
18.36 
29.70 
26.95 
'27.10 
17.69 
22.25 

27-15 



17.41 SOs 
20.89 SO3 
14.94 SO3 
95.68 SO3 
161.27 SO3 
6 8.44 SO3 
•1.51 SO3 
45.10 S 
26.19 s 



6.97 
8.37 

5-98 
38.32 
64.58 
3.38 
0.61 
45.10 
26.19 



a Rainfall at Garforth for 1907. 

h Record for approximately eitflit months. 

Since ma I of the information concerning the quantity of sulfur in 
rainwater has been obtained from data resulting from the analyses 
<■! the rain tailing in or near cities or towns, the application of such 

data to rural districts is highly speculative. In an attempt to approxi- 
mate the amount of this element the rain is likely to furnish the soil 
in any particular section certain factors must be carefully considered, 
the principal ones bein^ the position of the area in question with 
reference to railroads, to cities of varying sizes, to the direction of 
the prevailing winds, and to the sulfur content of the coal used in 
the region under consideration. 



AGRONOMIC AFFAIRS. 



229 



If sulfur is applied to soils for the express purpose of supplying 
the needs of plants with an essential element, with the thought that it 
may be a limiting factor in crop production, its application is unneces- 
sary in many localities and is certainly not practical in the vicinity of 
large industrial cities. 

Literature Cited. 

1. Crowther, Charles, and Ruston, A. G. The nature, distribution and 

effects upon vegetation of atmospheric impurities in and near an indus- 
trial town. In Jour. Agr. Sci., 4: 20-55. 191 1. 

2. Miller, X. H. J. The amounts of nitrogen as ammonia and as nitric acid 

and of chlorine in the rain water collected at Rothamsted. In Jour. 
Agr. Sci., 1 : 280-303. 1905. 

3. Peck. E. L. Nitrogen, chlorine, and sulphates in rain and snow. In Chem. 

News, 116: 283. 1917. 

4. Stewart, Robert. Sulfur in relation to soil fertility. 111. Agr. Expt. Sta. 

Bui. 227. 1920. 

5. Trieschmanx, J. E Nitrogen and other compounds in rain and snow. In 

Chem. News, 119: 49. 1919. 

6. Yityx, I. A. The quantities of chlorine and sulphur carried into the soil 

by atmospheric precipitation. In Zhur. Optyn. Agron. (Russ. Jour. Expt. 
Landw.) v. 12, no. 1, p. 20-32. 1911. Abs. in Expt. Sta. Rec, 25: 317. 
1911. 

AGRONOMIC AFFAIRS. 

DELAY IN MAY ISSUE. 

The long delay in publication of the May issue of the Journal has 
been due to the printers' strike, which has been in effect since May I. 
Naturally considerable time is required to break in new compositors 
for the setting of technical and tabular matter, but the printers now 
assure us that our work will be handled promptly and it is hoped that 
no further delays will occur. 

MEMBERSHIP CHANGES. 

In the April issue a membership of 636 was reported. Since then 
14. new members have been added and 1 lapsed member has been 
reinstated, while 4 have resigned, making a net gain of 1 1 and a total 
membership at this time of 647. 

BOOK REVIEW. 

The Soils and Agriculture of the Southern States. By Hugh 
Hammond Bennett. 399 p., illus. New York, Macmillan & Co., 1921. 
The United States Bureau of Soils started its systematic classification 



23O JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



and mapping- of field soils nearly a quarter of a century ago. The 
results of this nation-wide survey have been published from time to 
time and the information is available either in the advance sheets of 
the Bureau of Soils or in the annual reports of its field operations. 
A summing up of the work has also been made in a purely technical 
way in several Departmental bulletins. Nevertheless, neither the 
trained agronomist nor the student of agriculture, not to mention the 
farmer, has found it an easy task to correlate the vast amount of 
accurate agricultural information compiled in the various soil survey 
reports. 

Air. Bennett's book has been prepared with the idea of making 
available in a readable f ornr to teacher, student, and farmer alike the 
available information relative to the soils and agriculture of the 
eighteen Southern and Southeastern States. While the material has 
come largely from the publications of the Bureau of Soils, the reader 
is constantly aware of the fact that the author has had an unlimited 
stock of personal information to draw upon which was gained thru 
his years of field work in the survey. This has been a great asset in 
enabling- him to present the material in such an interesting manner. 

As might well be expected, the author has laid particular stress on 
the relation of the soil to crop production. In this connection not 
(•nl)- is the adaptation of crops to certain soils emphasized, but at the 
same time the bearing which the soil has on the system of fertilization 
is forcefully presented. His discussion of the relation of the soil to 
the fertilizer requirements is of particular significance because of the 
recent tendency on the part of certain groups to minimize the soil 
characteristics in recommending fertilizer treatments. 

The Soils and Agriculture of the Southern States " fills a real 
need in our agricultural literature. Not only will it be read with 
interest and profit by the various agricultural workers of the country, 
but it should also prove of inestimable value as a reference book. 
Unfortunately it will not receive the attention on the part of the 
farmers which it deserves. One would hardly dare predict the value 
that would result to American agriculture if every farmer of the 
eighteen State- covered should acquire the information contained in 
this volume. Let us hope that this book will prove to be, as the author 
suggests, " Volume I of a series covering the soils of all sections of 
the United States and their relation to agriculture." 

E. L. Worth en. 

NOTES AND NEWS. 

I*. V. ( anion, for the pasl two years agronomist at the Montana 
- and Station, is now director of the I 'ranch Agricultural Col- 
lege, ( edar, Utah. 

I ' ), ( roiiicr. formerly assistant agronomist at the Indiana station, 
i . now associate professor of farm crops al Pennsylvania State 

College. 



AGRONOMIC AFFAIRS. 



231 



John W. Gilmore. professor of agronomy in the California college 
of agriculture and agronomist at the station, is now in Chile as ex- 
change professor from the United States at the University of Chile 
for the academic year 1921-22. 

W. H. Jordan, director of the New York State station at Geneva, 
X. Y., for the past twenty-five years, has resigned, effective July 1, 
and was succeeded by R. W. Thatcher, formerly dean of the Minne- 
sota college and director of the station. He has been succeeded in 
Minnesota by R. C. Coffey, animal husbandman at the Illinois station. 
U. P. Hedrick has been made vice-director of the New York State 
station. 

David D. Long, in charge of the soil survey at the Georgia college, 
has resigned to become soil specialist for the Soil Improvement Com- 
mittee of the Southern Fertilizer Association. 

W. J. Morse, plant pathologist at the Maine station, has been ap- 
pointed director of that station. 

Theodore E. Odland, assistant professor of agronomy at the Minne- 
sota college, resigned May 1 to take charge of the crop production 
work at the West Virginia station. 

George R. Quesenberry, formerly in charge of the college farm at 
the New Mexico college, has been made professor of agronomy in 
that institution. Donaldson Ryder, formerly assistant agronomist, 
has resigned to engage in farming, and has been succeeded by W. T. 
Conway. 

Chas. H. Ruzicka, for the past several years superintendent of the 
Williston (N. Dak.) substation, has been made foreman of the station 
farm at Fargo, N. Dak. 

Dr. John M. Thomas, president of Middlebury College since 1908, 
has been appointed president of the Pennsylvania college. 

A. D. Wilson, director of extension in Minnesota, has resigned to 
engage in farming and has been succeeded by Frank W. Peck, of the 
Federal office of farm management. 



232 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



CONFERENCE OF WESTERN AGRONOMISTS. 

A conference of agronomists of the Rocky Mountain and Pacific 
Coast States was held in Arizona August 24, 25, and 26. The first 
day was spent at the University of Arizona at Tucson, and the subse- 
quent days at the experiment stations at Sacaton and Mesa and in 
taking an auto trip through the principal agricultural portions of the 
Salt River Valley. The trip from Tucson to Sacaton and Mesa was 
made by automobile and gave a fine opportunity for observing the 
general agriculture of that region. 

President von KleinSmid of the University of Arizona entertained 
the members of the conference at luncheon on the 24th. 

Papers or discussions were presented before the meeting as 
follows : 

A new method of study of tree transpiration and its effect on the ground water 

supply, G. E. Smith, University of Arizona. 
A small grain thresher' for head row work or nursery plats, E. H. Pressley, 

University of Arizona. 
Xew wheat varieties for the Great Basin, George Stewart, Utah Agricultural 

College. 

The improvement of potatoes by selection within clonal lines, George Stewart, 

Utah Agricultural College. 
Sunflowers for silage, H. N. Vinall, United States Department of Agriculture. 
The Federation wheats of California, V. H. Florell, United States Department 

of Agriculture. 

Tillage methods for wheat production on the dry lands of the Columbia River 
Basin, D. E. Stephens, United States Department of Agriculture. 

Root nematodes in their relation to western agronomy, G. H. Godfrey, United 
States Department of Agriculture. 

How best to present the results of experimental work to farmers, Round table 
discussion. 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. September-October, 1921. Nos. 6, 7 



THE INFLUENCE OF WHEAT STRAW ON THE ACCUMULATION 
OF NITRATES IN THE SOIL. 1 

Herschel Scott. 2 

The extensive application of straw to cropped land in recent years 
and the observance of certain injurious effects which seemed to in- 
dicate nitrogen hunger suggested a study of the effect of straw on the 
accumulation of nitrates in the soil. 

The general problem of organic matter and nitrification has occupied 
the attention of a large number of investigators and the literature on 
the subject is extensive. 

REVIEW OF LITERATURE. 
Winogradsky and Omeliansky (26) , 3 working with pure cultures 
in solution, showed that the activity of the nitrifying organisms is 
inhibited by the presence of even slight traces of organic matter. The 
results secured by them are as follows : 

Substance. Percent retarded. Percent inhibited. 

Glucose 0.0250 to 0.05 O.20O 

Peptone 0250 .200 

NH 3 0005 .015 

According to Percival (19), 3 ''The presence of very small amounts 
of easily oxidized organic compounds is detrimental to the growth and 

1 Contribution No. 18 from the Department of Agronomy, Kansas Agricul- 
tural Experiment Station, Manhattan, Kans. Received for publication October 
16, 1920. 

2 Offered in partial fulfillment of the requirements for the degree of Master 
of Science at the Kansas State Agricultural College. 

3 Reference is to " Literature cited," p. 257. 



233 



234 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



activity of both types of nitrifying organisms, the nitrite-forming 
bacteria being more sensitive in this regard than the nitrate-forming 
species. On this account the nitrification process does not begin until 
all the organic material has been fermented by other species of 
bacteria." 

Conn (5) states that " The building of nitrates will not take place in 
the soil as long as there is any considerable amount of organic material 
or free ammonia present. The nitrate-forming bacteria will not grow 
either in the presence of organic material or ammonia. It is not until 
after decomposition has been completed and practically all the organic 
compounds used up, that the nitrifying germs can begin to act." 

Snyder (23) observes that "The principal organic food of the 
nitrifying organisms is the organic matter of the soil and it is only 
when organic matter is incorporated with the soil that it can serve as 
food for the nitrifying organisms. In the presence of large amounts 
of organic matter, as in a manure pile, nitrification does not take place. 
It occurs only when organic matter is largely diluted with soil." 

Pitchard (22) found that ".Increasing the quantity of organic 
nitrogen from 1 to 3 grams per kilogram of soil was clearly unfavor- 
able to nitrification. Not only the relative proportions, but also the 
absolute quantities, of nitric nitrogen decreased as the amount of 
organic matter increased." 

Withers and Fraps (27) studied the nitrifying power and humus 
content of a number of typical North Carolina soils. They found the 
greatest nitrifying power in the soil containing the highest percentage 
of humus, in this case 2.86, and state that most of the soils high in 
humus arc high in nitrifying power. The addition of 3.22 percent of 
dried barnyard manure to the soil in three cases hindered nitrification 
during four or five weeks, and in a fourth case nitrification did not 
proceed vigorously. 

Lbhtlis (15) showed that where soil extract is inoculated with fresh 
-oil, nitrification is not inhibited even when enough organic matter is 
present to enable denitrifying organisms to grow. 

Karpinsky and Niklewsky (12) have shown that, when used in 
mixed cultures, various organic compounds in low concentration 

dearly favor nitrification, and that humus-rich soil nitrifies more 
rapidly than humus-poor soil. 

Coleman ( | I found thai in both pure and mixed cultures, dextrose, 
Cane lUgar, glycerine, and lactose in small quantities favor nitrification, 
and that an amount of dextrose found inhibitive in solution was not 
inhibit ive in sand cultures. 



SCOTTI ACCUMULATION OF SOIL NITRATES. 



235 



Stevens and Withers (24) found that nitrifications with pure and 
mixed cultures is inhibited less by organic matter such as peptone, 
cottonseed meal, and cow manure in soils than it is in solutions, and 
state that " organic matter even to a large amount, as considered 
agriculturally, is not necessarily inimical to the functioning of the nitri- 
fying organism in the field." The authors also present data showing 
that where cow manure was added to soil at rates varying from 1 ton 
to 160 tons per acre, good nitrification occurred in all cases, and 
organic matter was still present at the end of the period. The rate of 
nitrification was inversely proportional to the amount of manure 
added. 

Potter and Snyder (21) found, in pot cultures, a striking decrease 
in amount of nitrate nitrogen as increasing amounts of manure were 
added to the soil. 

Hill (9) found that the addition of 0.6 percent straw, 0.44 percent 
clover, 0.44 percent soybeans, or 0.22 percent blue grass to a soil under 
greenhouse conditions increased nitrification. The addition of 0.3 
percent paper, however, to a soil under similar conditions did not in- 
crease nitrification except after a long period of incubation. He cites 
Lemmerman and Tazenke (14) to the effect that a slight loss of 
nitrogen occurs when green manure is added to a sandy soil, and 
states that these authors believe that the crude fiber in green manures 
is indirectly proportional to the soluble nitrogen. This he suggests 
is perhaps the reason for the common belief that straw decreases the 
nitrogen in the soil. 

Pfeiffer (20) noted a harmful effect from the application of straw. 

Bredemann (1) found that the addition of organic matter, such as 
hay and sugar, produced a harmful effect the first year, but a bene- 
ficial effect was noted the next year. 

Engberding (6) found that the addition of straw and sugar to the 
soil at first increased and later decreased the bacteria in the soil. The 
ammonifying and nitrogen fixing groups were increased and the 
nitrifying group decreased. 

Frankfurt and Duschechkin (7) found that green manure under 
field conditions caused a diminution of nitrate content of the soil. 
Both legumes and non-legumes showed this effect. 

Warrington (25) states that richness of the soil in organic matter, 
the presence of CaCO s or some other base, aeration of the soil, the 
presence of a certain proportion of water, and a summer temperature 
are the conditions recognized as most favorable to nitrification. On 
the other hand, the presence of fresh organic matter or the growth of 



236 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

molds was known to be injurious. He also describes experiments 
showing that soil in solution containing nitrates and sugar exercises 
an energetic denitrifying action, and cites as a well established 
principle that the presence of oxidizable organic matter is an indis- 
pensable requisite for the deoxidation of nitrates. 

McBeth and Wright (17), studying the factors limiting nitrification, 
report that 2 percent of glucose and 2 percent of starch disappeared 
from soil in less than seven days. Cellulose disappeared more slowly. 
The addition of glucose and starch caused a rapid disappearance of 
nitrates from eastern and western soils ; with cellulose the disappear- 
ance was less rapid. Two percent of fresh horse manure caused only 
a partial disappearance of soil nitrates. After seven days in eastern 
soil and twenty-one days in western soil, nitrification became active, 
causing an increase in nitrates. Nitrification took place rapidly in 
rotted manure. The addition of 5 percent cellulose to the manure 
caused rapid denitrification. 

Clark and Adams (3) added sugar, molasses, butyric acid, alcohol, 
and filtered wool-scouring waste in slowly increasing amounts to a 
solution in which the nitrogen content was constant. When the ratio 
of carbon to nitrogen remained low, active nitrification occurred. 
Where nitrification was checked by the large amounts of carbon applied, 
it did not again become active until the ratio of carbon to nitrogen 
was considerably reduced. Where nitrification had been checked but 
not entirely stopped by the carbon, it was reestablished by increasing 
the amount of nitrogen in the liquid and keeping the carbon constant, 
i.e., by reducing the carbon-nitrogen ratio. Where nitrogen as NH 4 €1 
was added to the liquid, nitrification was not checked by carbonaceous 
bodies, even when very large amounts were added. 

According to the work of Greaves and Carter (8) the application ot 
manure, even so large an amount as 25 tons per acre, produces a very 
great increase in the nitrifying powers of the soil. The authors state 
thai there is no indication that denitrification occurs in the presence 
of the largest quantities of organic matter applied in this experiment. 

Ililtner and I'eters ( 10) found that the growth of oats was retarded 

by the application of lupine straw. Lupines were not affected. The 
-,<Tond scar after the application the growth of oats was greater after 
the lupine Straw than after oats. The increase: in yield was about 50 
percent, 10 that the net effect of tlx- lupine straw for the first and 
second years was beneficial. Where oats followed oats the application of 

straw resulted in a I0S8 the first year and a gain of only .about 19 
I it the ' ' Ond year, making a net loss for the two years. 



SCOTT I ACCUMULATION OF SOIL NITRATES. 



237 



Chirikov and Shmuk (2), studying the influence of moisture and in- 
creasing amounts of straw on the progress of denitrification in sandy 
loam soil with the moisture content remaining constant, found that 
the yield of oats decreased with increasing amounts of straw. The 
addition of CaCO s with the straw reduced to an appreciable extent 
the injurious effect of the latter but did not wholly overcome it. The 
diminished growth resulting from the application of these substances 
was not due to denitrification in a strict sense but to the fact that the 
nitrates in the soil were converted into albuminoid compounds which 
are less assimilable by green plants than are nitrates. 

Niklewsky (18) conducted pot experiments with oats in a sandy 
loess soil deficient in plant food. Straw was found to have an unfavor- 
able influence on the utilization of (NH 4 ) 2 S0 4 with low concentra- 
tions, and a favorable influence with high concentrations. Straw 
hastened the diffusion of NaNO s in the soil and had a favorable in- 
fluence on its utilization with low concentrations. 

Wright (28) showed that where such substances as straw and fresh 
manure, cellulose, glucose, and starch were added to soils the nitrate 
nitrogen was reduced and the process of nitrification was inhibited 
until decomposition was well advanced. 

Jensen (11), studying the relation of nitrification to field factors, 
found no evident relation between the variation in nitrates and in 
temperature, whether the mean maximum, mean minimum, or general 
mean temperature was considered. 

King and Whitson (13) compared the rate of nitrification at 
constant temperatures of 35 F., 48 F., 68° F., and 90 F., and 
found that the rate of nitrification at 90 was 6.33 times more rapid 
than at 35 F., and at 68° about twice as rapid as at 48 . 

Lyon and Bizzell (16) found that in unplanted soil nitrates usually 
increased in the spring with the rise in temperature. After mid- 
summer there was little apparent relation between temperature and 
nitrate content until late autumn. In the case of cropped soil no 
consistent relation between nitrate content and temperature was ob- 
servable during midsummer. 

EXPERIMENTAL DATA. 

In the present study observations were made both on soils kept in 
jars in the greenhouse and on soils in the field. All nitrate data 
reported were obtained by the phenoldisulfuric acid colorimetric 
method of analysis. Parallel determinations were made from time to 



238 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



time, using the aluminum reduction method on portions of the same 
filtrate. The results from the two methods were found to be in close 
agreement. 

Greenhouse Investigations. 

For the greenhouse work twenty-five 4-gallon jars were used. 
These jars were filled with a thoroly pulverized silt loam soil, which 
was made up to optimum moisture content. 

Five of the jars were used as checks and received no treatment 
other than the addition of water required to maintain the moisture con- 
tent at the optimum. Finely cut wheat straw was added at the rate 
of 1 percent to the soil in ten jars. Five of these received in addition 
to the straw 0.1 percent of (NH 4 ) 2 S0 4 . Wheat straw was added at 
the rate of 0.5 percent to the soil in ten remaining jars. Ammonium 
sulfate was also added to half of these at the rate of 0.1 percent. 

This arrangement provided five jars of each treatment, as follows : 

Nos. 1 to 5 — No treatment. 

Xos. 6 to 10 — 1 percent wheat straw. 

Nos. 11 to 15 — 1 percent wheat straw and 0.1 percent (NH^-SO*. 
Nos. 16 to 20 — 0.5 percent wheat straw. 

Nos. 21 to 25 — 0.5 percent wheat straw and 0.1 percent (NHO-SO-i. 

Nitrates in the soil were determined at the beginning of the test 
and on a sample from each jar at 2, 4, 6, 8, 10, 12, 16, 20, 
24, 28, 32, 36, and 48 weeks thereafter. The soil was thoroly stirred 
and the moisture content made up to optimum each week. A second 
addition of 0.1 percent of (NH 4 ) 2 S0 4 was made to those jars re- 
ceiving that treatment at the end of four weeks and a third addition 
at the end of eight weeks. 




O f I $ i J> II M 10 18 20 22 M 28 28 JO 32 34 36 38 40 42 44 40 48 
Tifnt in w9*Ma 

I '/ Gftpfa ihowiflfl effect "f application <>f straw and of straw and am- 
nx. mum sulfate on nitrate nertuniilal ion in soils. 



SCOTT : ACCUMULATION OF SOIL NITRATES. 



239 



A tube was used in sampling. By this means a core of soil was 
taken to the depth of the jar. Duplicate determinations were made 
on each sample, furnishing an average of 10 determinations on each 
of the five soil treatments. These results are presented in Table 1 
and graphically in figure 9. 

Table i. — Effect of application of straw and of straw and ammonium sulfate 
on nitrate accumulation in soils under greenhouse, conditions, shown 
as nitrates in parts per million of dry soil. 



Time in weeks. 



Treatment. 





















2 


4 


6 


8 


10 


12 


No treatment 


55-6 


790 


117. 2 


160. 1 


217.6 


180.8 


169.0 


1 percent straw 


55-6 


11.6 


4.2 


11.6 


15-2 


14-5 


30.0 


1 percent straw and 0.1 per- 
















cent (NH 4 ) 2 S0 4 


55-6 


48.9 


237.0 


808.3 


822.0 


842.0 


887.0 


0.5 percent straw 


55-6 


23-4 


21.7 


36.7 


68.5 


ll.o 


80.0 


0.5 percent straw and 0.1 
















percent (NH 4 ) 2 S0 4 


55-6 


100.0 


228.0 


533-4 


646.0 


812.0 


820.0 




16 


20 


24 


28 


32 


36 


48 


No treatment 


152.0 


207.5 


293 


309.1 


352.2 


313-6 


292.0 




40.5 


71.6 


149-5 


167.9 


310.6 


270.6 


199-8 








1 percent straw and 0.1 per- 
















cent (NH 4 ) 2 S0 4 


936.5 


1,240.2 


1,422.0 


1,265.0 


2,084.0 


1,809.4 


1,635-0 


0.5 percent straw 


86.9 


122.7 


180.2 


202.0 


276.2 


285.0 


322.0 


0.5 percent straw and 0.1 
















percent (NH 4 ) 2 S0 4 


869.0 


1,219.8 


1,413-6 


i,455-o 


1,668.0 


1,407-2 


1,423-0 



As indicated in Table 1 and in figure 9, the addition of 1 percent and 
0.5 percent wheat straw reduced the nitrate content as compared with 
the check, the reduction being greater for the larger amount of straw. 
The disappearance of nitrates in the soil to which straw had been 
added was marked during the first two weeks, and the deficiency 
continued in a lesser degree during the third and fourth weeks, after 
which recovery began. At the end of eight weeks the nitrate content 
of the soil to which 0.5 percent straw had been added reached the 
original content, while the soil to which 1 percent straw had been 
added required 18 weeks to regain its original quantity of nitrate. 

The nitrate content of the soil to which 0.5 percent straw had been 
added rose steadily until the end of the experiment, when it slightly 
surpassed that of the untreated soil, which had dropped during the 
last 12 weeks. 

The nitrate content of the soil to which 1 percent straw had been 
added remained well below that of both the untreated soil and that to 



240 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



which 0.5 percent straw had been added except in one instance, where 
it went above the latter. 

The soil to which both straw and (NH 4 ) 2 S0 4 had been added 
suffered a slight loss of nitrates the first two weeks but recovered 
quickly. By the end of the sixth week it had reached a concentration 
of 800 parts per million and a maximum concentration of nearly 2,100 
parts per million at the end of the 32d week, as compared with a 
maximum of only about 350 for the untreated and 310 for the soil 
with straw alone. 

Similar results were secured when (NH 4 ) 2 S0 4 was added with 0.5 
percent of straw. 

Field Experiments. 

The field work consisted of comparing the effects on the develop- 
ment of nitrates, the moisture content of the soil, and soil temperature 
of different amounts of straw applied in two different ways both to an 
uncropped soil and as a top dressing on wheat. 

The soil used is known as the Derby silt loam. Samples for nitrate 
determinations were secured early in the fall, early in the spring, and 
at approximately semimonthly intervals until October of the following 
year. Samples were taken of the following depths : o to 6 inches ; 7 
to 12 inches ; 13 to 24 inches ; and 25 to 36 inches. Composite samples 
consisting of two or more cores from each plat were used. 

STRAW APPLIED AS A TOP DRESSING ON WHEAT. 

This experiment was begun in the fall of 191 5. Twelve plats 
arranged in groups of three each (fig. 10) according to treatment the 

previous year were used. 
1 Mais 1 , 2, and 3 had been 
cultivated to a depth of 3 
Inches during the summer 
of 1915. On plats 4, 5, 
and ( i weeds had been al- 
lowed to grow. Plats 7, 

8, and () had been kept 

tree from all vegetation 
but had not been culti- 
Vv. ro. Arran«,,n,.nt of plats ns,,l to deter- VatC(l Mats IO, 1 1, gad 

mine .i„ effect oi trtm applied as a top 12 1,a(1 Deen cultivated to 
dressing on wheat in the fall of 1015. a depth of f> inches. The 

different treatments during [915 had caused marked differences in the 

nitrate content <»f the different plats at seeding time, as shown in 

I fantfl 2 of Table 2. 



PLOT 


PLOT 


PLOT 




PLOT 


PLOT 


PLOT 


9 


8 


7 




3 


2 


1 



PLOT 


PLOT 


PLOT 




PLOT 


PLOT 


PLOT 


12 


II 


10 




6 


5 


4 



SCOTT : ACCUMULATION OF SOIL NITRATES. 



2 4 I 



On plats 1, 4, 7, and 10 straw at the rate of 4 tons per acre 
was applied in November, 191 5. On plats 2, 5, 8, and 11 straw at the 
rate of 2 tons per acre was applied in November, 191 5. The other 
plats were used as check plats, no straw being applied. 

A marked difference in the growth of the wheat was apparent early 
in the spring. This difference persisted to the time of harvest. The 
plats without straw made the best growth, the plants being uniformly 
vigorous and of a good green color. The wheat top-dressed at the 
rate of 2 tons per acre made a fairly good growth but was unequal to 
the check plats. The growth was very much reduced on the plats to 
which 4 tons of straw had been applied. The plants were noticeably 
yellow in color and lacking in vigor. These relations were especially 
pronounced on plats 4, 5, and 6, where the nitrate content at seeding 
time was very low, and were much less apparent on plats 10, 11, and 
12, where the nitrate content was high at seeding time. The strawed 
plots of each group were from a week to ten days later in heading than 
were the check plats, and remained green after the latter were ripe. 
This may be attributed to the larger percentage of moisture present in 
the soil in the former at harvest time. Excepting plats 10, 11, and 12, 
which were highest in nitrates at seeding time, the check plats or 
those to which no straw was applied produced the best yield. The 
straw appeared to have little effect on the yield of plats 11 and 12 
where the nitrates at seeding time were high, indicating that the straw 
reduced the yield on the other plats by reducing nitrification. This 
conclusion is strengthened by the appearance of the plants in the 
spring and their growth during the summer. 



Table 2. — Effect of straw applied as a top dressing to wheat in the fall. 



Plat 
No. 


Nitrates at 


Tons of 
straw per 
acre. 


Yield. 


Nitrates at 
harvest, parts 
per million. 


Percent mois- 


seeding, parts 
per million. 


Grain, bus. 
per acre. 


Stiaw, tons 
per acre. 


ture in surface 
12 inches at 
harvest. 


1 


172.5 


4 


17.4 


2.70 


76.0 


29.0 


2 


172.5 


2 


16.4 


2.44 


5i-5 


29.0 


3 


172.5 


None 


29.2 


3.80 


81. 1 


19.7 


4 


5-2 


4 


9-6 


•58 


26.7 


28.2 


5 


5-2 


2 


13-5 


•58 


31-0 


27.2 


6 


5-2 


None 


24.2 


1. 16 


59-9 


19.0 


7 


130. 1 


4 


16.4 


3-13 


64.8 


26.5 


8 


130. 1 


2 


17.4 


2.84 


87.1 


27.2 


9 


130. 1 


None 


23.7 


4-38 


91.6 


25.0 


10 


253-5 


4 


33-8 


3-54 


58.9 


26.5 


11 


253-5 


2 


28.0 


3-34 


62.4 


29.7 


12 


253o 


None 


30.0 


3-8o 


66.3 


25.0 



242 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

The treatments, the yields of grain and straw per acre, the nitrates 
at seeding time and at harvest, and the percentage of moisture in the 
surface foot of soil at harvest are given in Table 2. 



THE EFFECT OF STRAW ON NITRIFICATION IN UNCROPPED SOIL. 

In this experiment straw was applied in two different ways and at 
two different rates to plats which had been treated alike the previous 
year, i.e., in 191 5. On plats I, 4, and 7 straw was applied at the rate 
of 4 tons per acre in November, 191 5, and worked into the surface 6 
inches. On plats 9, 12, and 15 straw was applied at the rate of 4 tons 
per acre in November, 191 5, as a top dressing. On plats 2, 5, and 8 
straw was applied at the rate of 2 tons per acre in November, 191 5, 
and worked into the surface 6 inches. On plats 10, 13, and 16 straw 
was applied at the rate of 2 tons per acre in November, 191 5, as a top 
dressing. The remaining plats (plats 3, 6, 11, and 14) were left 
untreated for comparison. Plats 1, 2, and 3 were cultivated during 
the spring and summer of 1916. Plats 4, 5, 6, 7, and 8 were scraped 
during the spring and summer of 1916. The weeds on the remaining 
plats were pulled during the season of 191 6. The plats were 6 feet by 
10 feet and were separated by 2-foot alleys. The plats as a whole 
joined those on which the effect of straw as a top dressing was studied, 
being separated from them by a 5-foot alley. The arrangement of the 
plats is. shown in figure II. 

The average nitrate 
content to a depth of 
3 feet of all plats, ex- 
pressed as parts per mil- 
lion at the time of apply- 
ing the straw in the fall, 
in the Spring, and at in- 
tervals during the fol- 
lowing season, is given 
in Table 3 and sum- 
Nie nit rale content of the surface 6 inches of 



PLOT 
7 



PLOT 
6 



PLOT 
5 



PLOT 
4 



PLOT 
3 



PLOT 
2 



PLOT 
I 



PLOT 
16 



PLOT 
15 



PLOT 
14 



PLOT 
13 



PLOT 
12 



PLOT 
II 



PLOT 

10 



PLOT 
9 



Fte. 11. Arrangement of plats for the study 

of the effect of straw on un cropped land. 



niarized in Table 4. 
lOll U expressed graphically in figures 12, 13, 14, 15, and 16 



SCOTT I ACCUMULATION OF SOIL NITRATES. 



243 



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SCOTT : ACCUMULATION OF SOIL NITRATES. 



245 



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JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



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SCOTT : ACCUMULATION OF SOIL NITRATES. 247 



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SCOTT : ACCUMULATION OF SOIL NITRATES. 



249 



Table 4. — Effect of application of straw on the nitrate content of the upper 6 

inches of soil. 









Nitrates expressed 


as parts per million. 




Plat 


x x ca until 1 • 


Nov. 


Apr. 


Apr. 


May 


May 


May 


June 


June 


No. 




29, 


5. 


18. 


1, 


15. 


30, 


15. 


28, 






I 9 I S- 


1916. 


1916. 


1916. 


1916. 


1916. 


1916. 


1910. 


1 


/I fnriQ ctrau^ 

-f LUllO Olidn 




57-0 


36.9 


19-5 


14.9 


20.1 


52.0 


43-0 


2 




43-9 


41.4 


33-2 


30.3 


22.4 


25.6 


39-0 


50.2 


1 



None 


4O.0 


7 A 2 


81 * 

OA. 3 




3 I'* 


32.6 


43-5 


51.0 


4 and 7 


4 tons straw 6 


78.0 


32.7 


44-3 


34-8 


21.7 


26.6 


31.7 


102.7 


5 and 8 


2 tons straw-* 


71.9 


79-6 


53-1 


47-4 


24-5 


37-2 


3i-3 


80.1 


6, 11 and 


















14 


None 6 


50.4 


101.9 


102.3 


83-7 


89-3 


72.5 


69.2 


no. 6 


9, 12 and 


















IS 


4 tons straw c 


67-3 


57-5 


45-9 


28.9 


16.3 


16.3 


18.8 


12.5 


10, 13 and 
















16 


2 tons straw 


77-9 


75-o 


74-0 


58.6 


19.1 


17.7 


18.5 


22.8 


6, 11 and 












14 


None c 


56.4 


101.9 


103-3 


83.7 


89-3 


72.5 


69.2 


110.6 



Plat 
No. 


Treatment. 


Nitrates 


expressed as parts per million. 


July 
12, 
1916. 


July 
24, 
1916. 


Aug. 

7, 
1916. 


Aug. 

21, 
1916. 


Sept. 

4. 
1916. 


Sept. 

18, 
1916. 


Oct. 

6, 
1916. 


■ • * 


4 tons straw* 


59-3 


82.8 


101.0 


109.4 


96.6 


66.4 


118. 


2 


2 tons straw 


59-8 


102.5 


93-0 


101.6 


112. 3 


41.6 


97-6 


3 


None a 


46.5 


84.0 


70.0 


94.4 


117. 8 


63.6 


97-4 


4 and 7 


4 tons straw 6 


68.5 


IIO.O 


166.5 


!57-5 


166.9 


169.5 


207.0 


5 and 8 


2 tons straw 6 


95-5 


118. 


157-7 


165.2 


142.8 


242.5 


178.0 


6, 11 and 


















14 


None 6 


123.5 


146.8 


185-5 


I9I-7 


150.0 


150.5 


155-0 


9, 12 and 


















15 


4 tons straw c 


30.1 


40.4 


57-2 


58.8 


45-4 


53-5 


43-6 


10, 13 and 


















16 


2 tons straw- c 


30.6 


40.6 


81.3 


82.2 


66.4 


73-4 


132.0 


6, 11 and 


















14 


None c 


123-5 


146.8 


185-5 


I9I-7 


150.0 


150.5 


155-4 



Straw worked in, in the fall; ground cultivated during following season. 
h Straw worked in, in the fall ; weeds removed by scraping during the fol- 
lowing season. 

c Straw applied as a top dressing in the fall; weeds pulled during the fol- 
lowing season. 

The most marked effect of the straw no matter how applied was to 
reduce the nitrate content the following spring. The difference be- 
tween the strawed plats and the checks was especially marked when • 
the straw was applied as a top dressing. Where the straw had been 



250 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



worked into the soil and the ground was cultivated the following 
summer, the nitrate content of the strawed plats, after about June I, 
was nearly equal to and at times exceeded that of the check plats. The 
same tendency was observed on the plats which were scraped, but in 
this case the increase in nitrates after about June I was much greater, 
the total amount at the end of the season being nearly twice as much 
as in the cultivated plats otherwise treated the same. 

















.No i 


'reati 


nent, 


N 

plot 


* ;P 
3 


(Ul ^ 




























































V- 


/ 




s 






















r , 
i J 
1 n 


\ 


\ 












t 

f 








V 


T 


x 

X 


































/ 



















5 18 I 15 50 15 28 12 24 7 21 4 18 6 

APRIL M AY JUNE JULV- AUG. SEPT. OCT. 

Fig. 12. Graph showing effect on nitrates in the surface soil of straw worked 
into the ground (Ground cultivated during the following season). 



Four tons of straw, when applied as a top dressing, had a greater 
inhibiting effect than the 2-ton rate, but the effect was not very differ- 
ent when the straw was worked into the ground. 

Scraping the surface without disturbing it more than necessary 
greatly increased the development of nitrates as compared with culti- 
vating. 

MoiSTCKK AM) Tl-.M I'KK ATl'KK STUDIES. 

[fl connection w ith the nitrate studies heretofore reported, moisture 
determinations were made on each sample (Table 5) and the tempera- 
ture for each treatment recorded by means of soil thermographs (Table 
6 Seasonal rainfall is shown in Table 7. 

Th< plat to which straw had been applied contained slightly more 

moisture than the untreated plats, the difference being greatest where 
'raw was applied as a top dressing. The difference in all cases 

was not great. 



SCOTT : ACCUMULATION Of SOIL NITRATES. 



200 



150 



100 



50 



4 Tons per acre,- plots 4 and 7 

2 i plots 5 and 8 

No treatment; plots 6, II, and 14 
















\ / 






















\ 




/ \ 
/ ) 

/ 


















/ » 

/ — U- 






-r — 


/ 

« — • 
















/ 

/ 


if 
























/i 
St 

y i 














*s 

N 




\ 




A 


-\ 

*y \ 

\ 


j. 






















i / 
i/ 
i/ 


























if 
ij 











































5 18 I' 15 30 15 28 12 24 7 21 4 18 6 

APRIL MAY UUNE JULY AUG. SEPT. OCT. 

Fig. 13. Graph showing effect on nitrates in the surface soil of different ap- 
plications of straw worked into the ground (Weeds removed during the fol- 
lowing season by scraping). 



200 



•a 

1 



150 



100 



50 













7 -n/nrs/n 

Mo treatment; plots J, 6, II 


15, and 76 
and 14/ 




\ 

\ 


















1 




/ 

/ 




\ 

\ 

\ 


s 

/ 

s 
















1 

1 
























/ 


7 — 
1 
















\ 


-\ — 




/ 


/ 










N 










\ 




/ 

/ 








/ * 




■s. 



























































5 18 I 15 30 15 28 12 24 7 21 4 18 6 

APRIL MAY UUNE JULY AUG. SEPT. OCT. 

Fig. 14. Graph showing effect on nitrates in the surface soil of straw applied 

as a top dressing. 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 5. — Effect of application of straw on the moisture content of the sur- 
face foot of the soil. 



Plat 
No. 


Treatment. 


Moisture content, percent. 


Apr. 

5. 
1916. 


Apr. 

18, 
1916. 


May 

1 , 
1916. 


May 

15. 
1916. 


May 
30, 
1916. 


June 
15. 
1916. 


June 
28, 
1916. 


July 
17. 
1916. 


1 


4 tons straw" 


22.0 


23.2 


27.0 


26.7 


24-5 


26.5 


22.7 


22.7 


2 


2 tons straw" 


22.0 


23.0 


26.5 


26.2 


19.7 


25.0 


22.0 


22.0 


•2 


None 


21.0 


23-0 


25.0 


25-5 


21.0 


24.2 


21.2 


21.2 


4 and 7 


4 tons straw 6 


19-3 


21.2 


25.2 


25-7 


19-3 


23-5 


22.0 


18.7 


5 and 8 


2 tons straw 6 


20.2 


20.3 


24.0 


25-7 


17.0 


24.2 


21.6 


18.8 


6, 11 and 


None 6 


















14 


21.0 


20.6 


24.4 


25.0 


22.0 


22.7 


20.0 


17-5 


9, 12 and 




















15 


4 tons straw c 


24.4 


24.6 


26.1 


25.8 


26.4 


22.7 


23.0 


19-5 


10, 13 and 




















16 


2 tons straw 6 


22.7 


23.2 


25.6 


25-0 


25-5 


22.5 


19.8 


15-9 


6, 11 and 




















14 


None c 


21.0 


20.6 


24.4 


25.0 


22.0 


22.7 


20.0 


17-5 



Plat 

No. 


Treatment. 


Moisture content, percent. 


July 
24, 
1916. 


Aug. 

7. 
1916. 


Aug. 

21, 
1916. 


Sept. 

4. 
1916. 


Sept. 

18, 
1916. 


Oct. 

6, 
1916. 


Aver- 
age. 


1 


4 tons straw 


15-7 


150 


17.6 


15-4 


25.8 


20.5 


21.8 


2 


2 tons straw 


15.0 


16.2 


19.8 


17.6 


26.6 


19.8 


21.5 


3 


None 


13.0 


16.2 


17.O 


17.7 


25.8 


19.0 


20.7 


4 and 7 


4 tons straw 6 


14.0 


13-5 


12.2 


14-3 


23-4 


18.3 


19.4 


5 and 8 


2 tons straw 6 


15-8 


13.0 


9.2 




22.4 


17.9 


18.9 


6, 1 1 and 


















14 


None 6 


10.9 


131 


17.4 


16.8 


22.0 


18.4 


19-3 


p, 12 and 


















15 


4 tons straw 6 


16.0 


15.0 


17.4 


17.4 


26.9 


20.7 


21.8 


10. 13 and 


















10 


2 tons straw 6 


12.5 


13-3 


[8.0 


i.S-7 


255 


18.7 


20.3 


6, 11 and 


















M 


None 6 


10.9 


I3.I 


17.4 


16.S 


22.0 


18.4 


19-3 



''Straw worked in, in the fall; ground cultivated during following season. 
* Straw worked in, in the fall; weeds reinoved hy scraping during the fol- 
lowing season. 

r Straw applied ns a top dressing in the fall; weeds pulled during the follow- 
ing season. 



SCOTT : ACCUMULATION OF SOIL NITRATES. 



253 



200 



o 



150 



I 

! 
1 



Fig. 



100 



50 



No treatment; weeds scraped; plots 6, II, and 14 

4 Tons straw per acre worked in-, weeds scraped, 1916; 

plots 4 and 7 

4 " "-.cultivated, 1916; plot I 

A " " » " as a top dressing weeds pulled, 191$ 

p/ots9J2 f andl5. 




5 18 

APRIL 



I 15 30 15 28 12 24 7 2\ 4 18 6 

M A V JUNE JULY AUG. SEPT. OCT. 

15. Graph showing effect on the nitrates in the surface soil of straw ap- 
plied in various ways. 



Scraped, plot 6 






/ 




\ 

A— 




















/ 

/ 




\ 




















/ 

/ 
* 






















/ 










✓ 

/ 

/ 


\ 

\ 
1 






"V 

\ 




\ 




/ 

/ 




/ 




✓ 

/ 

/ 


/ 


\ 

\ 
\ 

\ 


/ 

/ 




V 




\ 




I 




f— 

/ 

/ 

/ 

/ 


X 






\ 


/ 








X 

N 

N 















































5 18 I 15 30 15 28 12 24 7 21 4 18 6 

APRIL MAY JUNE JULY AUG. SEPT. OCT. 

Fig. 16. Graph showing relative effect on the nitrate content of the surface 
soil of cultivating and removing the weeds by scraping. 



254 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 6. — Mean maximum, mean minimum and average weekly temperatures 

in degrees F. 

MEAN MAXIMUM TEMPERATURES. 



AT I 

Alontn. 


Wppl- 
VV CCK. 


Treatment. 


None. 


4 tons 
worked in. 


2 tons 
worked in. 


4 tons as 
a top . 
dressing. 


2 tons as 

a top 
dressing. 


.April 


1 


60.0 




61.0 


54-o 


57-o 






u «5- / 












3 


62.O 




67.O 


59-o 


60.1 




4 


70.1 




70.4 


59-3 


61.5 


M 

- 


c 

o 


68.0 




68.0 


59-0 


61.7 










8 C A 


69-5 






»7 
1 


73-0 




72.7 


64.0 


65.3 




8 


87.0 




86.4 


76.0 


77.0 




o 


94.4 




93-0 


79-5 


81.7 




10 


87-5 




86.5 


73-5 


75-7 






8r A 

05.0 




8/1 8 
04.0 


75-5 


76.1 




12 


91.0 


90.5 


91.0 


78.4 


81.4 




13 


104.5 


104.0 


IO4.O 


86.4 


91.8 


j «uy 


14 


1 13.0 


1 1 1.4 


IO9.8 


90.3 


99.0 




T C 


in. 7 


110. 7 


IO9.3 


92.7 


103.0 




16 


111.5 


110.0 


109. 1 


92.7 


97.6 




17 


116. 


115.0 


115. 


94-7 


102.7 




T 8 
1 O 


119. 8 


H7-5 


II8.0 


97.1 


106.8 




19 


115. 


112. 


"3-7 




100. 1 




20 


112. 


100.0 


no. 4 


93-3 


97.0 




21 


114. 


IIO.O 


112. 


97-7 


98.4 




22 


99.0 


93-4 


96.4 


85.5 


85.0 


September 


23 


101.7 


99.0 


IOI.O 


90.7 


89.7 




24 


87.5 


84.7 


87.1 


76.5 


76.0 




25 


92.6 


88.8 


92.0 


79.0 


79.2 




MIC AN 


MINIMI M 


TEMPERATURES. 







/\pru 


I 


41.0 




38.3 


4i -5 


46.5 




2 


47.6 




45-i 


46.1 


47-3 




3 


45-0 




47-5 


49.1 


47.O 




4 


46.7 




47.1 


46.3 


46.3 


May 


5 


47-5 




48.8 


46. s 


48.5 




6 






60.8 


56.5 


57-7 




7 


49.1 




51.0 


52.5 


49-8 




8 


63.7 




63-7 


64.1 


63.0 


Juno 


9 


635 




64.5 


64.4 


63-7 




1 


56.3 




57-8 


58.5 


57-5 




1 1 


62.0 




62.1 


61.8 


6 1 .4 




1 2 


O4.8 


6.i-7 


65-7 


64.4 


65.3 






71.1 


70.7 


72.0 


69.8 


7 ( >-3 



SCOTT I ACCUMULATION OF SOIL NITRATES 



255 



Table 6. — Mean maximum, mean minimum and average weekly temperatures 
in degrees F. (Continued) . 



MEAN MINIMUM TEMPERATURES. 







Treatment. 


"\Ionth. 


Week. 


None. 


4 tons 


2 tons 


4 tons as 


2 tons as 






vorked in. 


^vorked in. 


a top 
dressing. 


a top 
dressing. 


July 


14 


72-3 


t D- u 






74-7 




15 


76.8 


78.4 


78.1 


74-1 


78.8 




16 


75-7 


74-3 


75-0 


72.5 


75-i 




17 


77-1 


78.1 


78.8 


74-4 


77-4 




18 


82.4 


83-3 


83-4 


78.7 


83-5 


19 


79-7 


80.3 


8O.5 




81.3 




20 


78.3 


78.5 


79.1 


76-3 


78.8 




21 


71.0 


71.8 


72.8 


70.1 


74.1 




22 


61.4 


63-0 


64.8 


63-0 


65.8 


September 


23 


73-4 


71.0 


72.5 


70.3 


72.1 




24 


55-4 


53-4 


56.1 


54-4 


55-3 




25 


54-7 


53-2 


55-6 


53-8 


55-o 




AVERAGE WEEKLY 


TEMPERATURES. 








I 


50.5 




49.6 


47-7 


5i-7 


2 


55-6 




54-0 


50.6 


5i-9 




3 


53-5 




57-2 


54-0 


53-5 




4 


58.4 




58.7 


52.8 


53-9 




5 


57-5 




58.4 


52.7 


55-i 


6 






73-1 


03-0 


f\ 4 8 
O4.0 






61.0 




61.8 


58.2 


57-5 




8 


75-3 




75-0 


70.0 


70.0 




9 


78.9 




78.7 


71.9 


72.7 


10 


71.9 




72.1 


66.0 


66.6 




11 


73-5 




73-4 


68.6 


68.7 




12 


77-9 


72.1 


78.3 


71-3 


73-3 




13 


87.7 


87-3 


83-0 


78.1 


81.0 


July. 


14 


92.6 


83.2 


82.8 


81.0 


86.8 


15 


94.2 


84-5 


83-7 


83.1 


90.9 




16 


93-6 


92.1 


92.0 


82.6 


86.3 




17 


96.5 


960 


96.9 


84.2 


90.0 




18 


IOI.I 


■ 100. 1 


1 100.7 


87-9 


95-1 


19 


97-3 


96.1 


97.1 


84.8 


90.7 




20 


95-1 


93-2 


94-7 


87.9 




21 


92.5 


78.2 


80.6 




75-4 




22 


80.2 


78.2 


80.6 


74.2 


75-4 




23 
24 


87-5 
71.4 


85-0 
69.0 


86.7 
71.6 


80.5 
65-4 


80.9 
65.6 




25 


73-6 


71.0 


73-8 


66.4 


67.1 



256 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

The untreated plats and the plats on which the straw was worked 
into the soil showed very uniform temperatures. Where the straw was 
applied as top dressing, the temperatures were consistently lower than 
the untreated plats, the average for the 2-ton application being 3.3 F. 
less and for the 4-ton application 8.3 F. less than the untreated soil. 



Table 7. — Daily rainfall in incites at Manhattan, Kans., April to September, 

1916. 



Day. 


April. 


May. 


June. 


• July. 


August. 


September. 


1 














2 














3 




0.07 










4 






0.50 








5 






.40 








6 


O.IO 




.41 




















7. . 


.08 










2.38 


8 














9 














10 






.62 








11 




1.29 


1.06 






3.48 


12 


•37 




2-95 






1. 19 


13 




•23 










14 


.28 


i-95 










15 




.18 


•44 








16 






•05 








17 














18 














19 


•25 




•99 


2-35 






20 ; 






•39 












1.2$ 










22 














23 




.64 










24 


.02 












25- • ■ 






.04 






.26 


26 






.62 




0.05 




27 




.28 










28 














29 


1.04 


•53 










30 














31 




23 






• 13 




Total 


2.14 


6.65 


8-47 


2-35 


0.18 


7-3i 



SIMM ARY. 

Application- of straw to soil in the greenhouse caused a marked 
decrease in the nitrate content. The loss was proportional to the 
amount of straw added. As decomposition of the straw progressed 
the nitrates in the soil increased but remained lower in the presence 
of straw than in the untreated soil. The addition of nitrogen as 

nH 4 ) ^ r >, with the Btfaw caused a more rapid accumulation of 
nitrates. 



SCOTT : ACCUMULATION OF SOIL NITRATES. 



257 



Heavy fall applications of straw to wheat growing in the field 
retarded growth the following spring, delayed the ripening of the 
grain, and reduced the yield except on soils having a high nitrate 
content when the straw was applied. 

Four tons of straw per acre worked into the surface 6 inches of 
uncropped soil resulted in a lower nitrate content the following spring, 
but during the summer the accumulation of nitrates was equal to that 
in the untreated plats. 

Two tons of straw per acre worked into the surface 6 inches did not 
lower the nitrate content of the soil the following spring. 

Four tons of straw applied as a top dressing reduced the nitrate 
content the following spring and summer. This treatment showed, 
thruout the summer, the highest moisture content, the lowest tempera- 
ture, and the lowest nitrate content of any of the treatments. 

Two tons of straw applied to the surface did not show an appreci- 
able. decrease in nitrates the following spring and the accumulation of 
nitrates was fairly great by the end of summer. 

LITERATURE CITED. 

1. Bredemaxx, G. Tests of a bacteria inoculating preparation. In Landw. 

Jahrb'., Bd. 43, PP- 669-695. 1913. 

2. Chirikov, F. V., and Shmuk, A. A. Experiments on denitrification. In 

Izv. Moskov. Selsk. Khoz. Inst. 19, no. 2, pp. 270-286. 1913. Abs. in 
Internat. Inst. Agr. Mo. Bui. Agr. Intel, and Plant Diseases, v. 4, no. 
10, pp. 1528-1529. 1913. 

3. Clark, H. W., and Adams, Geo. O. The influence of carbon on nitrifica- 

tion. In Jour. Indus, and Engin. Chem., v. 4, p. 272. 1912. 

4. Colemax, L. C. Untersuchungen iiber Nitrifikation. In Centbl. Bakt, Abt. 

2, Bd. 20, p. 401. 1908. 

5. Coxx, H. W. Agricultural Bacteriology. 103 p. Philadelphia, 1901. 

6. Exgberdixg, Diedrich. Vergleichende Untersuchungen iiber die Baktier- 

enzahl im Ackerboden in ihrer Abhangigkeit von ausseren Einflussen. 
In Centbl. Bakt, Abt. 2, Bd. 23, p. 601. 1909. 

7. Fraxkfort, S., and Duschechkin, A. Course of nitrification under the 

conditions of field experiments. In Russ. Jour. Expt. Landw., v. 8, no. 
6, p. 707. Abs. in Expt. Sta. Record, v. 20, no. 6, p. 519. 1909. 

8. Greaves, J. E., and Carter, E. G. Influence of barnyard manure and water 

upon the bacterial activities of the soil. In Jour. Agr. Research, v. 6, 
no. 23, p. 898. 1916. 

9. Hill, H. H. Effect of green manuring on soil nitrates under greenhouse 

conditions. Va. Agr. Expt. Sta. Tech. Bui. 6. 1913. 

10. Hiltxer, L., and Peters, L. The action of straw manure on fertility of 

soils. In Expt. Sta. Record, v. 19, no. 2, p. 119. 1907. 

11. Jexsex, C. A. Relation of nitrification to field factors. U. S. Dept. Agr., 

Bur. Plant Indus. Bui. 273. 1910. 



258 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

12. Karpixsky, A., and Niklewsky, B. Uber den Einflusz organischer Ver- 

bindungen auf den Verlauf der Nitrifikation in unreinen Kultur'en. Ext. 
D. Bui. de V Acad. d. Sci. de Cracovie. 1907. 

13. Kixg. F. H., and Whitson, A. R. Development and distribution of ni- 

trates in cultivated soils. Wis. Agr. Expt. Sta. Bui. 93, 18 p. 1902. 

14. Lem MERMAN, O.. and Tazenko, A. Untersuchungen iiber die Umsetzung 

des stickstoffs Verschiedener. In Landw. Jahrb., Bd. 38, pp. 101-113. 
1909. 

15. Lohnis, F. Uber Nitrifikation und Denitrifikation in der Ackererde. In 

Centbl. Bakt. Abt. 2, Bd. 12, p. 448. 1912. 

16. Lyox, T. L., and Bizzell, J. A. Some relations of certain higher plants 

to the formation of nitrates in soils. Cornell Univ. Agr. Expt. Sta. Mem- 
oir 1. 1913. 

17. McBeth, I. G., and Wright, R. C. Certain factors limiting nitrification 

Abs. in Science, v. 35, no. 897, p. 392. 1912. 

18. Xiklewsky, B. The influence of the distribution of nitrogenous fertilizers 

and straw in soil' on plant production. In Ztschr. Landw. Versuchsw. 
Osterr., 18, no. 12, pp. 674-690. 191 5. Abs. in Expt. Sta. Record, v. 35, 
no. 6, p. 518. 1916. 

19. Percival, John. Agricultural Botany, 765 p. Henry Holt & Co., N. Y. 

1900. 

20. Pffifffr, T. The nitrogen economy of cultivated soils. In Landw. Inst. 

Breslau, v. 4, p. 733. Abs. in Expt. Sta. Record, v. 21, p. 417. 1909. 

21. Pitchard, P. Effect of different proportions of clay and organic nitrogen 

on the fixation of atmospheric nitrogen, the conservation of nitrogen, and 
nitrification. Abs. in Expt. Sta. Record, v. 3, p. 636. 1892. 

22. Pottfr. R. S., and Snyder, R. S. Determination of amino acids and ni- 

trates in soils. Iowa Agr. Expt. Sta. Research Bui. 24, pp. 327-352. 1915. 

23. Sxydfr, Harry. Soils and Fertilizers. 137 p. The Macmillan Co., N. Y. 

1909. 

24. STEVENS, F. L., and WITHERS, W. A. The inhibition of nitrification of or- 

ganic matter, compared in soils and in solutions. In Centbl. Bakt., Abt. 
2, Bd. 27, p. 169. 1910. 

25. Warrington, Robt. Lectures on the Investigations at Rothamsted Experi- 

ment Station. Vol. 3, Nitrification, p. 43, Govt. Printing Office, Wash- 
ington. 1892. 

26. WlNOGRADSKY, S., and Omfxiansky, V. Ueber den Einflusz der organ- 

i hen Substanzetl auf die Arbeit der nitrifizierenden Mikrobien. In 
Ut-ntbl. Rakt.. Abt. 2. Bd. 5. p. 329- 1899. 

27. WmiiKs, W. A., and FRAPS, (i. S. Nitrifying powers of typical North 

Carolina soils. Rpt. N. C. Agr. Expt. Sta., 1902-1903, PP- 57-63- i<K>3- 

28. WlXGHTj R. C The influence <>f certain organic materials upon the trans- 

formation of soil nitrogen. /;/ Jour. Amer. Soc. Agron., v. 7, no. 5, p. 
103. iQi 5- 



A STUDY OF HYBRID OATS, A VENA STERILIS X AVENA 
ORIENTALIS. 1 



S. Wakabayashi. 2 

The present research was undertaken to collect some facts regarding 
the inheritance of smut resistance, sterility, panicle shape, color of the 
flowering glume, dwarfness, and correlations among these characters 
in the F 2 and F 3 of Red Rustproof (Avena sterilis) X Black Tar- 
tarian oats {Avena orientalis). Smut resistance, sterility, and dwarf- 
ness directly affect the production of oats and, therefore, these factors 
are very important from an economic as well as a scientific viewpoint. 

According to the estimate by the Plant Disease Survey of the U. S. 
Department of Agriculture, the loss of oats due to smut is as shown 
in Table i. 



Table i. — Losses due to oat smuts in Washington in 1917, 1918, and 1919, and 
in the United States in 1917 and 19 18. 





Washington. 


United States. 


Year. 


Production, 
bushels. 


Loss due to smuts. 


Production, 
bushels. 


Loss due to smuts. 


Bushels. 


Percent. 


Bushels. 


Percent. 


1917 


11,242,000 


348,000 


3-3 


1,587,286,000 


91,648,000 


5.26 


1918 


8,370,000 


251,000 


3-0 


i.538,359.ooo 


64,396,000 


4.20 


IQI9 


12,800,000 


384,000 


3-0 









Some fields in Washington have lost as high as 25 percent of the 
oat crop on account of smut. By far the greatest loss in the State is 
due to covered smut, Ustilago laevis avenae. If a variety of oats 
immune to covered smut and as high in production as our best com- 
mercial varieties could be produced, it would save 3 percent of the 
crop, which is worth about. $300,000 at present prices. The loss due 
to sterility and dwarfness has not been measured, but it is safe to 
assume that these characters diminish to a considerable extent the 
total production of the country. 

1 Contribution from Department of Farm Crops, Washington Agricultural 
Experiment Station, Pullman, Wash. Received for publication October 25, 
1920. 

2 The writer desires, to acknowledge courtesies extended by the Washington 
Agricultural Experiment Station, and particularly by Prof. E. F. Gaines, under 
whose direction this work was undertaken. 



259 



260 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Historical. 

The writer has been unable to find anything in print on the re- 
sistance of oats to covered smut. 3 As to rust resistance, Parker (3, 4)* 
found that the Avena sterilis group is more resistant to both Puccinia 
graminis avenae and P. lolii avenae than the A. sativa group, but there 
are some varieties of the sativa group which are susceptible while 
others are resistant. He favors the multiple factor theory. 

Appearance of dwarf plants has not been frequently reported in the 
literature. Warburton (5) reports the sudden appearance of dwarf 
plants as a simple Mendelian recessive in a head-row selection of a 
common oat variety, Victory-. 

Gaines (1), Nilsson-Ehle (2), Wilson (6), and others have found 
that the black color of the floral glume in the oat is a simple Mendelian 
factor in some crosses and composed of multiple factors in others. 

The shape of the panicle was found to be very irregular. The side 
shape bred true, while some intermediate panicles also bred true and 
others segregated irregularly, indicating multiple factors for this 
characteristic also. 

Method and Material. 

The female parent, Red Rustproof (Wash. No. 768) belongs to 
Arena sterilis. In the varietal test of 1919 it was about 32 inches tall, 
fine and stiff; panicles small, upright, and pyramidal, floral glumes 
greasy in appearance and very slightly reddish tinted ; outer glumes 
not so white as those of A. sativa; bristles at the bottom of the first 
floret abundant and very prominent ; awns twisted once, white ; stool- 
ing rather pronounced and with many green tillers which did not 
mature before harvest. 

Black Tartarian (Wash. No. 762) belongs to Avena orientalis. It 
had straw in 1919 about 42 inches in height, very large but rather soft. 
Stooling was less marked than in the case of Avena sterilis. Panicles 
of side Or horsetnane type, Long, and hearing more kernels than those 
of Ave mi sterilis; floral glumes dark brownish or black; awns dark 
and twisted twice; bristles few and small. 

( onipari-on of the two parents in tabular form is shown in Table 2. 
• : ' 1 '1 ' 1 1 r u... written, Reed hftl reported that Avena sterilis forms 
i! ually arc n-MManl to covered smut, while A. sativa forms usually are sus- 
<- ;.hUc. \(. r . Kxpt. Sta. Kcsearch Rul. 37, 1020). 

' U< )< retire I iy uumher is to " Literature cited," ]>. 266. 



WAKABAYASHI : HYBRID OATS. 



26l 



Table 2— Comparison of Red Rustproof and Black Tartarian oats in certain 

characters. 



Characteristics. 


Rod Rustproof 


BlcicK Tjirtcirio,n . 


Average height, inches 


32 


42 


Average number of culms per plant (including 






green ones) 


8.3 


2-3 


Average number of kernels per panicle 


45 


169 


Susceptibility to smut 


Immune 


Susceptible 






(ave. 34 percent) 


Percent of sterile flowers 


25 


14 




Pyramidal 


One-sided 


Average length of panicle, inches 


5 


11 



These parents were crossed reciprocally in 1916, and F 1 plants 
from three seeds were grown in 191 7. The seed from one was sown in 
1918, and 112 F 2 plants were produced. One panicle from each of 
these 112 Red Rustproof X Black Tartarian plants was saved, and in 
1919 the kernels from these were inoculated with covered smut of 
oats and sown in separate rows to test their smut resistance. Seed of 
both parents was similarly treated, as was also the seed from the sib 
and the reciprocal plant grown in 1917. One of these produced 49 
and the other 26 plants in 1919, the small numbers perhaps being due 
in part to the fact that the seeds were inoculated with smut. The F 3 
rows contained an average of only 12.2 plants per row. 

The kernels of a representative panicle from each of the F 2 plants 
were classified according to the color of the floral glumes into BB 
(black), Bb (brown), and bb (white), and the numbers of sterile and 
fertile flowers were also recorded. 

The F 3 plants were separated according to the color of the floral 
glumes and panicle type, i.e., they were first divided into black and 
white, then each class was further divided into pyramidal, intermedi- 
ate, and side type, and the number of each was recorded. Since it was 
somewhat difficult to separate Bb from BB, the only color separation 
was black and white. One representative panicle from each plant was 
then collected and thrashed separately. The percentage of sterility 
was calculated from actual counts of sterile and fertile flowers. Ten 
typical panicles of each parent were thrashed and counted for compari- 
son. For calculating the smut loss, the smutted plants were first sepa- 
rated into those all smutted and those partly smutted. Then the 
partly smutted group of each row was separated into smutted and 
nonsmutted panicles. Those panicles which were half or less smutted 
were counted as non-smutted while those with more than half smut 
were recorded smutted. The product of the percentage of the partly 



262 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



smutted plants and the percentage of smut on the partly smutted plants 
was added to that of the percentage of the plants all smutted, to get the 
percentage of loss due to smut for the row. 

Results, 
smut resistance. 

Red Rustproof has never shown a single indication of smutting, 
altho sown repeatedly under conditions favoring maximum smut in- 
fection. Black Tartarian has produced from 25 to 40 percent of smut 
under the same conditions. The F x and F 2 have never produced a 
trace of smut. In the Fo smut was found in 12 rows, while 95 were 
immune. The amount of smut produced in the 12 rows was 15, 12, 
9, S. 4. 4, 4. 3, 3, 2, 2, and 0.1 percent respectively. The most sus- 
ceptible Fo row produced less than half as much smut as the susceptible 
parent. As to the cause of immunity of F 2 and pronounced resistance 
in F 8 , the results indicate the existence of multiple factors. Keeping 
in mind the fact that the susceptible parent showed smut on less than 
half the plants, the F 3 is nearly what is to be expected if the immunity 
of Red Rustproof is caused by three independent dominant factors 
any one of which would prevent the appearance of covered smut. 

The fact that resistance is dominant is unusual, inasmuch as it has 
been reported as recessive in wheat yellow rust by BifTen and by 
Nilsson-Ehle and in stinking smut of wheat by Gaines. 

STERILITY. 

The record shows that Red Rustproof is higher in sterility than 
Black Tartarian. Their crosses are comparatively high in sterility, 
tho decreasingly so generation after generation because of sterile 
Strains eliminating themselves. When a representative panicle from 
each individual was counted for sterility it was noticed that some 
were 100 percent sterile, while a few were less than 5 percent sterile. 
Table 3 shows sterility in the parents, F lf F 2 , and F 8 rows. 



TABLE 3 Comparative sterility of Red Rustproof and Black Tartarian oats 
and the first three generations of hybrids between them. 



Variety. 


Number of 


Number <>f 


Sterility, 




fertile flowers. 


sterile flowers. 


percent. 




454 


112 


25 




1.4.S2 


246 


M 




122 


197 


62 


Red Rnttprool V Wtck Tartarian, Kj 


2.H02 




57 


I<< -1 H i t p [<.<,! / }'.\:k k Tartarian, I« a 




2.^.935 


3« 




(,H 


167 


7i 


Hlark Tartarian / Hrr] Ku«t proof V2 


1.158 


620 


35 



WAKABAYASHI : HYBRID OATS. 



263 



Table 3 shows decreasing sterility in succeeding generations when 
averaged, but the increased fertility of some of the F 3 rows offers a 
suggestion of multiple factors and is of economic importance. 

COLOR OF THE FLORAL GLUMES. 

Seeds from F 2 plants of 1918 were separated into three classes 
according to the color, 24 BB (black) 60 Bb (intermediate black), 
and 26 bb (white). This artificial classification of the color of the 
floral glumes was shown to be inaccurate by sowing these seeds and 
observing the segregation. The 24 classified as BB proved to be 
17 BB and 6 Bb, 1 not producing plants. The 60 classified as Bb 
proved to be 22 BB and 32 Bb, 5 not producing any plants and 1 pro- 
ducing only 2 white plants. Those classified as bb all bred true to 
whiteness. 

The F 3 is far from the ratio 1:2:1. However, if the two colored 
classes are combined, the ratio is 72 percent with color and 28 percent 
white, which approaches the 3 : 1 ratio. This shows the difficulty of 
distinguishing BB from Bb. The F 2 sib and the reciprocal in 1919 
produced an average of 24 percent of plants with white floral glumes. 
This makes it certain that color in this cross reacts as a unit factor. 

SHAPE OF PANICLE. 

Much time was spent in an attempt to classify the F 2 and F 3 
panicle types segregating in 1919, but owing to the rapidity with 
which the material ripened and the changes produced by different 
stages of maturity the classification as presented is unsatisfactory 
and more or less unreliable. It is sufficiently accurate, however, to 
show that the inheritance of the side or horsemane type of panicle is 
recessive but produced by multiple factors. The F 2 of Black Tar- 
tarian X Red Rustproof produced 6 plants with side panicle and 43 
that varied thru all intermediate stages to the pyramidal type. The 
reciprocal in which Red Rustproof was used as the pistillate parent 
seemed to show a greater tendency toward the side type in the F 2 . 
Eight plants were so classified in a row that produced only 18 others 
that were intermediate or pyramidal. The F 3 produced only 5 rows 
out of 107 that were 100 percent side type. Twenty-five rows were 
classified as pure pyramidal, but very few showed the wide spreading 
habit of Red Rustproof. The material was overripe before the classi- 
fication was completed. Of the 1,318 plants, 53 percent were classi- 
fied as pyramidal, 27 percent were put in the intermediate class, and 
20 percent seemed to be as near side type as the overripe Black Tar- 
tarian parent. 



26 4 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



DWARFNESS. 

In most cases those plants which were below 24 inches in height 
were counted as dwarf. However, some plants were counted as 
normal because of their vigor even tho they were a little below normal 
in height. 

The dwarf plants varied greatly in size and vigor. Some died 
early as the dry season came on, or remained in green tufts, or were 
scarcely able to produce seeds, while others produced almost normal 
seeds. In the F 8 , 143 plants were classified as dwarf out of 1,327. 
From one to many dwarfs appeared in 58 of the 107 rows. The 
others produced only normal plants. The two F 2 rows representing 
reciprocal crosses produced 75 plants, 7 of which were dwarfed. 

The appearance of dwarf plants among the progenies of a cross is 
not rare, tho the causes never have been studied to the writer's 
knowledge. Dwarfness and sterility may be due to the same or 
related causes, since the dwarf plants have weak, soft, slender culms 
with panicles high in percentage of sterile flowers. 

From the numbers of dwarf plants produced by the F 2 families 
(9.3 percent), it appears to be safe to assume that dwarfness is not 
produced by a simple factor. The fact that 51 percent of the F 2 
plants produced some dwarf plants in F 3 is a nearer approach to 
simple Mendelism. High mortality in dwarf plants may possibly have 
operated to change a 3 : 1 ratio to the figures actually obtained. In 
only two rows were all the plants dwarf. The dwarf F 3 parent 
plants were not recorded, but no doubt more than two were planted. 
The others evidently were not homozygous for the dwarf character 
or else the plants all died, as 5 rows were blank. If dwarfness were 
a simple recessive factor, 75 percent of all rows would give rise to 
dwarfs instead of 51 percent of the F 8 rows. However, it must be 
remembered thai the actual figures are the outcome after the weakness 
and sterility of seeds of a wide cross played their parts of elimination. 

CORRUPTION AMONG CHARACTERS CONSIDERED. 

It wai noted thai those 18 plants that produced smut were mostly 
dwarfed and had the side type of panicle, as is shown in Table 4. 
There leemi tO be some relation between the production of smut 

and dwarfness. li 1- difficult to say whether weak plants are apt to 

!»'• attacked by -nun or the presence of the smut fungus is a cause 
of dwarfne- 'I ho live smutted plants were not classified as dwarfs, 
\et the) urrc below the normal height because most of the healthy 

plant - ranged from 2H to 33 inches. 



WAKABAYASHI : HYBRID OATS. 



265 



Table 4. — Classification of smutted oat plants according to color of floral 
glume, shape of panicle, and height. 



Black side. 


Black 


White side. 


White 


White pyramidal. 






pyramidal. 






intermediate. 






Xo. 


Height , 


No. 


Height, 


No. 


Height, 


No. 


Height, 


No. 


Height, 


plants. 


inches. 


plants. 


inches. 


plants. 


inches. 


plants. 


inches. 


plants. 


inches. 


1 


6 


1 


28 


1 


16 


3 


20 


1 


L8 


1 


16 






2 


20 






1 


27 


1 


18 






2 


22 










1 


24 






1 


26 










1 


27 






■ 1 


27 











The table seems to indicate also a relation between smut suscepti- 
bility and white floral glume and also between smut susceptibility and 
side character of the panicle. However, dwarf plants are weak and 
usually retarded and the panicles show more or less close resemblance 
to the side character. The color of the floral glume also is not well 
developed, so that the white glumes and side panicles may have been 
wrongly classified, but this is hardly probable. 

Dwarf plants were difficult to separate according to the color and 
panicle shape because of their imperfect maturation. The number 
and height of the dwarf plants were as follows : 

Height, inches 9 12 13 14 15 16 17 18 19 20 21 22 23 

Xo. plants 1 6 5 5 7 1 8 20 17 12 23 26 12 

In the reciprocal F 2 , out of 49 plants there were six dwarfed, one 
measuring 16 inches and the rest 23 inches. In the F 2 sibs, out of 
26 plants, three were dwarfed, two measuring 18 inches and one 23 
inches. It also should be mentioned that the parent Red Rustproof 
sown for comparison had, out of 48 plants, four plants dwarfish, two 
measuring 20 inches, one 18 inches, and one 16 inches. These, how- 
ever, in their vigor and fecundity were more like normal. 

An analysis of the data shows that sterility is not in any way re- 
lated to the color of the floral glume or the shape of the panicle, as 
it is more or less evenly distributed among all the characters consid- 
ered. There is a definite correlation between dwarfness and sterility, 
but since the dwarf and normal plants were not kept separate in the 
laboratory where the sterility counts were made, it can not be put 
in tabular form. 

Summary. 

The F 1? F 2 , and F 3 generations of Red Rustproof (Avena sterilis) X 
Black Tartarian oats {Avena orientalis) were studied as to the re- 



266 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



sistance to smut, sterility, color of the floral glume, shape of the 
panicle, dwarfness of culm, and correlations among these characters. 

Resistance to smut is completely dominant and is caused by multi- 
ple factors. 

Sterility due to a wide cross is comparatively high in the F t , but 
decreases in succeeding generations. 

The black color of the floral glume of Black Tartarian is a simple 
Mendelian dominant character. 

The shape of the panicle is probably of multiple factors, if Men- 
delian. 

The production of dwarf plants was interfered with by sterility 
and it is difficult to state whether it is a simple Mendelian character. 

There seems to be some correlation between dwarfness and sterility 
and between smut susceptibility and dwarfness. There may also be 
correlation between smut susceptibility and white color of the floral 
glume and between susceptibility and the side character of the panicle. 

Sterility is not correlated with the color of the floral glume or the 
shape of the panicle. 

Literature Cited. 

1. Gaines, E. F. Inheritance in wheat, barley and oat hybrids. Wash. Agr. 

Expt. Sta. Bui. 135- 1917. 

2. Nilsson-Ehle, H. Kreuzungsuntersuchungen an Hafer und Weizen. In 

Lunds Universitets Arsskrift, 7: 1S2. 191 1. 

3. Parker, John H. Greenhouse experiments on the rust resistance of oat 

varieties. U. S. Dept. Agr. Bui. 629. 1918. 

4. . A preliminary study of the inheritance of rust resistance in oats. In 

Jour. Amer. Soc. Agnon., 12: 23-38. 1920. 

5. Wabbukton, C. W. The occurrence of dwarfness in oats. In Jour. Amer. 

Soc. Agron., 11: 72-76. 1919. 

6. Wilson, Johx H. The hybridization of cereals. In Jour. Agr. Sci., 2: 68- 

88. 1907. 




A STUDY OF THE LITERATURE CONCERNING POISONING OF 
CATTLE BY THE PRUSSIC ACID IN SORGHUM, SUDAN 
GRASS, AND JOHNSON GRASS. 1 

H. N. VlNALL. 2 

In countries where sorghum is important it has been known for 
many years that this, crop frequently causes the death of cattle when 
they are allowed to eat it in the green state. Pease (13) 3 states that in 
India the year 1877 was niarked by the death of great numbers of 
cattle due to eating sorghum. The season was especially dry and the 
crop was " semi-parched for want of rain." Sorghum poisoning was 
frequent also in 1887 and 1895, which were years of drouth. The 
natives believed that the sorghum plant became poisonous in dry years 
when attacked by a small insect which they called " bhaunri." The 
idea was that the cattle were poisoned by eating this insect. Other 
theories advanced included the belief that the sorghum leaves col- 
lected in the paunch and, by giving off gases, caused death by asphyxi- 
ation similar to hoven or bloating. 

Pease, in studying the matter in 1895, decided that the death of 
cattle was due to the consumption of nitrate of potash. He found in 
the stems of some withered sorghum plants as much as 25 percent of 
this salt, it being particularly abundant at the nodes. The symptoms 
of poisoning from nitrate of potash are somewhat similar to the 
symptoms of prussic acid poisoning. This theory of Pease was dis- 
pioved later, or at least it was found that it was not the cause of 
death in most cases of sorghum poisoning. 

In the United States the fact that cattle were poisoned by eating 
green sorghum was recognized by Hiltner (10) of the Nebraska sta- 
tion in 1900. This investigator made a chemical study of sorghum 
plants taken from a field which had caused the death of cattle, but 
failed to find the prussic acid, which no doubt was present. He 
found no substance in the plants which could have caused the death 
of the cattle and concludes as follows : 

1 Contribution from the Bureau of Plant Industry, U. S. Department of Agri- 
culture. Washington, D. C. Received for publication November 30, 1920. 

2 Agronomist, Office of Forage-Crop Investigations, Bureau of Plant Indus- 
try. 

3 Reference by number is to " Literature cited," p. 279. 

267 



268 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. » 



Negative results of an analysis are usually not satisfactory but in this case 
they are at least quite conclusive. In view of the analyses and' of the collateral 
evidence given, it seems certain that the toxic effect of this plant which mani- 
fests itself at times is not due to a chemical poison inherent in the plant and is 
not peculiar to the second growth alone. 

It was not until 1902 that the presence of HCN in sorghum plants 
was discovered. This was first reported by Dunstan and Henry (7), 
altho Slade, then assistant chemist at the Nebraska experiment sta- 
tion, suggested the probability of such a poison in sorghum in 1901 
(17) and actually isolated prussic acid from a sample of fresh 
sorghum about August 1, 1902 (18). His report of this discovery 
was sent to the Journal of the American Chemical Society for publi- 
cation on October 3, 1902. Avery (14, p. 10) asserts that Slade did 
not know until October 10 of the results obtained by the two English 
investigators. Dunstan and Henry's paper on this subject was re- 
ceived by the Royal Society of London April 24, read before that 
Society May 15, and published in the Chemical News of London in 
the issue of June 27, 1902. 

Avery '(14) continued the work of Slade and published in 1903 a 
rather complete summary of the results obtained at the Nebraska 
experiment station. The work of the three investigators, Peters, 
Slade, and Avery, left little room to doubt that- prussic acid was the 
direct cause of sorghum poisoning. 

That trouble from this source has been common in nearly every 
country where sorghum is grown to any extent is indicated by reports 
on sorghum poisoning from Australia, Java, India, Africa, Italy, and 
tin- W est Indies. It is known that this poisonous principle, prussic 
acid, exists in other plants belonging to the sorghum family. Craw- 
ford (5) found it in Johnson grass in 1906, and since that time other 
investigators, including Schroeder and Dammann (16), have reported 
hydrocyanic acid in this grass. 

No similar work had been done with Sudan grass until 1915, when 
Francis (X) "f the Oklahoma Agricultural Rxpcriment Station made 
determinations of the hydrocyanic acid in this grass. In 1919, 
Mcnaul and l)owcll ( 12), also of the Oklahoma station, reported a 
study of cyanogenesis in Sudan grass. 

no FORM M HTHK ii i-kcssic acid occurs in sokcjiium. 

Wcry, in the publication before mentioned, declares that prussic 
;•< i'l if not present in sorghums as such, but under certain conditions 

1- liberated from ;i glucoside by an enzyme in the plant. Olucosidcs 
01 thil son. he ' it' . are harmless and become dangerous only when 



vinall: prussic acid poisoning. 



269 



they are hydrolyzed and liberate prussic acid (14, p. 14). This 
cyanogenetic glucoside in sorghum is called dhurrin and is said by 
Dunstan and Henry (7) to have the empirical formula C 14 H 17 7 N, 
and " on hydrolysis with hot dilute hydrochloric acid or the enzyme 
emulsin, yielded one molecule each of prussic acid, parahydroxy-ben- 
zaldehyde and dextrose." 

The theory of Dunstan and Henry was that sorghum poisoning is 
caused by the dhurrin and emulsin coming together in the early proc- 
esses of digestion when the enzyme by the addition of water to the 
glucoside breaks the latter down and liberates the poisonous prussic 
acid. W orking independently and without knowledge of the findings 
of Dunstan and Henry in England, Slade and Avery (14, 17) arrived 
at practically the same conclusions. 

Dowell (6) agrees with the Nebraska and British investigators that 
the acid exists in sorghum only in the form of a glucoside. Willa- 
man (19) of the Minnesota station, however, claims that hydrocyanic 
acid is found in sorghum in both a glucosidic and a non-glucosidic 
form. He has support for this theory in the work of the Italians, 
Ravenna and Babini (15). These two investigators claimed to have 
found free prussic acid in sorghum leaves as well as in the leaves of 
cherry-laurel, peach, and flax. In their conclusions, however, they 
qualify their results somewhat by indicating how easy it would be 
for a small quantity of free HCN to be produced by autolysis during 
the progress of the experiment. The form in which HCN occurs in 
sorghum plants remains, therefore, a matter of dispute among chem- 
ists. The known facts regarding the comparative harmlessness of 
cured sorghum and the fact that the introduction of glucose into an 
animal's stomach renders the poison relatively innocuous seem to lend 
support to the glucoside theory. 

QUANTITY OF SORGHUM AND OF SUDAN GRASS NECESSARY TO PROVIDE A FATAL DOSE 

OF HCN. 

Avery found that 0.4 gram of the combined prussic acid was suffi- 
cient to make an animal very sick. It is probable, therefore, that 0.5 
to 0.6 gram or 0.02 ounce would be fatal to a mature animal in most 
cases. Table 1 indicates the quantity of sorghum or Sudan grass 
necessary for an animal to eat in order to take into its stomach this 
amount of prussic acid. The cases cited in the table are percentages 
obtained by actual analysis of samples as reported in different publi- 
cations. 



270 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table r. — Quantity of fresh Sudan grass or s org hum required to provide a 
sufficient amount of prussic acid to be fatal to cattle. 



L rop. 


r a- • 

Condition 01 crop. 


rrussic 
acid. 


A 

Authority. 


Material ne- 
cessary to 
provide fatal 
dose. 






Percent. 




Pounds. 








Menaul and 




Sudan grass . . 


Cut June 16, pis. 15 ins. tall 


0.0105 


Dowell (12) 


11.9 


Do 


Cut June 23 from same field 


0.0053 


do 


23.6 




Cut June 30 from same field 


0. 0069 


QO 


T 8 T 
I O. I 


Do 


Cut June 30 from same field 










(leaves only) 


0.0155 


• do 


8.1 


Do , 


Cut July 14 from same field 


0.0052 


do 


24.0 


Do , 


Cut July 31 from same field 










(second growth) 


0.0059 


do 


21.2 


Do 


Second growth, 15 ins. tall 


0.0042 


Francis (8) 


29.8 


Do 


Second growth, 17 ins. tall 


0.0021 


do 


59-6 


Do 


Second growth, 30 ins. tall 


0.0042 


do 


29.8 


Average 




0.0066 




18.9 


Sorghum .... 


Normal growth 30 ins. (Exp. 4a) 


0.0222 


Dowell (6) 


5-6 


Do 


Normal growth 30 ins. (Exp. 4b) 


0.0130 


do 


9.6 


Do 


Second growth 30 ins. (Exp. ia) 


0.0221 


do 


5-7 


Do 


Second growth 30 ins. (Exp. lb) 


0.0228 


do 


5-5 


Kafir 


Normal plant, 40 ins. tall 


0.0018 


Francis (8) 


69.4 


Average 




O.O164 




7-6 



Only analyses of sorghums made in Oklahoma by the same men 
who made the Sudan grass analyses are presented in Table 1, because 
the methods of chemists in determining the amount of prussic acid 
differ so widely that it is believed their results are not comparable. 
Care was used also in selecting from the many analyses of sorghum 
only those of plants in practically the same condition of growth and 
vigor as were the Sudan grass samples. With these precautions, it 
is believed that the comparison between Sudan grass and sorghum is 
fairly accurate. The average percentage of prussic acid in sorghum 
is seen to be about two and one half times that in Sudan grass. The 
average amounl of fresh material an animal would have to eat in 
order to ingest the ( >. ( >- ounce of prussic acid, considered as the 
amounl likely to prove fatal, is 18.9 pounds of Sudan grass and 'only 
7.6 pounds of sorghum. 

The proportion of acid in the leaves is nearly always greater than" 
it is in the Stems, however, and since the animal is likely to eat mostly 
leavei when turned into a field, X pounds of Sudan grass having the 
< of prussic acid shown by sample 4 in the table would be 
ufficienl tO kill as animal, if the liberation of the acid from the 
gUtCOSide was complete. Fortunately for stockmen, the conditions 



VTNALL : PRUSSIC ACID POISONING. 



271 



in the animal's stomach are not likely to cause complete hydrolysis 
of the dhurrin contained by the plant, otherwise fatalities among live 
stock pastured on Sudan grass would be much more numerous than 
they are. 

EFFECT OF CURING SORGHUM OR SUDAN GRASS ON HCN CONTENT. 

The very general belief among farmers that sorghum and Sudan 
grass cured as fodder or hay are usually safe to feed stock is confirmed 
by the investigations of Avery. He found that it was possible for an 
animal to consume 1.2 grams of combined prussic acid, when fed 
well-cured sorghum, without exhibiting any signs of poisoning. One 
third of this quantity taken into the stomach in fresh uncured sorghum 
would have been highly dangerous. Avery attributes this apparent 
harmlessness of the cured sorghum to the inactivity of the enzyme in 
dried plants. If the enzyme remains inactive, no free prussic acid is 
formed and the combined prussic acid in the form of the glucoside, 
dhurrin, does not cause trouble. 

Dowell has a different theory regarding the effect of curing sor- 
ghums. He states (6, p. 179) : 

A comparison of the percentage of hydrocyanic acid found in experiments 
la and lb with those in 2a and 2b shows that approximately three-fourths of 
the acid is set free in the process of drying. 

He also claims that where the material is dried out slowly more of 
the acid is volatilized than where the drying is accomplished quickly. 
His experiment 3a covering this point supports his conclusion thoroly, 
but the duplicate (experiment 3b) in which the sorghum was also 
dried quickly had remaining almost exactly the same amount of 
prussic acid as was found in experiment 2b where the material was 
dried slowly. If this theory of Dowell's is proved by later experi- 
ments it will have a practical application in determining the most de- 
sirable methods of curing sorghum and Sudan grass. 

EFFECT OF INJURY, ESPECIALLY BY DROUTH AND FROST, ON THE HCN CONTENT. 

Another belief of stockmen verified by experiments is that sorghum 
or Sudan grass injured by drouth or other adverse climatic conditions 
contains a larger quantity of prussic acid than where the crop has 
made a normal vigorous growth. In Table 2 a number of compara- 
ble analyses are presented showing the difference in prussic acid 
content of vigorous, healthy sorghum and that stunted by drouth or 
other adverse climatic conditions. 



2J2 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 2. — Percentage of prussic acid in healthy, vigorous sorghum and in that 
stunted by drouth or injured by frost. 











Percentage prussic 


c 

rop. 


Antlmrif" v 




Cause of 


acid. 




injury. 












Normal 
plants. 


Injured 
plants. 


Sorghum. . . . 


Peters, Slade, and Avery (.14, p. 


i3) a 


drouth 


0.0074 


0.0112 


Do 


Peters, Slade, and Avery (14, p. 


I3) a 


do 


.0076 


.0274 


Do 


Peters, Slade, and Avery (14, p. 


I3)° 


frost 


•0133 


.0082 


Kafir 


Francis (8, p. 3) 
Dowell (6, p. 178) 




do 


.0018 


.0037 
.0514 


Sorghum .... 




drouth 


.0222 


Do ... . 


Dowell (6, p. 178) 




do 


.0130 


.0450 


Do 


Willaman (20, p. 44)^ 




frost 


.0000 


.0017 


Do . , 


YVillaman (20, p. 44)** 




do 


.0055 


.0072 


Average 








.0089 


.0195 



In order to make the results of the analyses of the drouth injured plants 
comparable with those of the normal plants in which the percentage of HCN is 
given on the basis of fresh material the wilted plants from Cambridge, Nebr., 
are presumed to have lost 20 percent of their weight as evaporated moisture 
and the dried plants from Brighton, Colo., 70 percent of their weight. This 
reduces the expressed percentage of HCN very decidedly but it is believed 
that the percentages are thus made comparable. 

6 The percentages as given by Willaman are in the first instance for non- 
glucosidic, and in the second for glucosidic prussic acid. 

From a study of Table 2 it will be seen that in only one case is the 
observed percentage of HCN higher in normal plants than it is in 
plants injured by drouth or frost. The average for the series of 8 
analyses indicates that we can expect on an average over twice as 
much prussic acid in injured plants as in normal sorghum plants. 

T11 accepting the above conclusion, however, it is necessary to dis- 
tinguish between plants stunted by an acute spell of drouth or a frost, 
when they would otherwise have been growing vigorously, and those 
-United by a lack of plant food in the soil. It has been found by a 
number of investigators (1, 3, II, 16, and 21) that sorghum plants 
grown on a poor soil have less prussic acid in them than the plants 
grown "ii a rich soil, especially if the poor soil is low in nitrates. 
The addition of a nitrate fertilizer to a poor soil on which the sor- 
ghum wafl being grown invariably increased the ITCN content of the 

plants. 'Ibis fact, however, does not disprove the contention of 
\v« rv that sorghum injured by drouth usually had a higher HCN 
content than sorghum of normal growth, nor docs it set the findings 
of Avery at variance with those of Alway and Trumbull as suggested 
1 • Willaman and Weil (21, p. [8l |. A close analysis of the publica- 



vixall: prussic acid poisoning. 



273 



tions of the Nebraska investigators shows that their results are not 
necessarily conflicting on this point, altho their statements apparently 
give this impression. The crux of the matter seems to be that the 
HCN content of sorghum plants is increased by injury due to drouth, 
but is actually decreased by stunting of the plant thru lack of nourish- 
ment. Evidently an injury of any kind which, results in checking the 
growth of a sorghum plant results in an increase of HCN. 

The belief is common in Australia that sorghum plants attacked by 
insects are more poisonous than normal plants. Balfour (2) of the 
Gordon Memorial College, Khartoum, Egypt, analyzed two durra 
plants of approximately the same age. The plant affected with aphids 
contained 0.035 percent, and the normal or aphid-free plant only 
0.014 percent of HCN. This, of course, is only one analysis and 
can not be accepted as conclusive. 

EFFECT OF PLANT MATURITY OX THE HCX CONTEXT. 

Regarding the effect of maturity or age on the HCN content of 
sorghum plants, there is almost complete agreement among chemists 
as well as farmers. The percentage of prussic acid in sorghum 
plants decreases steadily from the time the plant begins growth until 
it ripens its seed, if the growth has been normal. In some cases 
where the growth has been interrupted by adverse climatic conditions 
there is noted an actual increase in the HCN content, but except for 
such abnormalities, sorghum or Sudan grass after it has headed out 
and set seed is usually safe to feed to cattle or horses. 

The most extensive and conclusive series of analyses bearing on 
this question are those of Willaman and West (21, 22) of the Minne- 
sota experiment station. These findings are supported by those of 
other investigators, but only a part of the results are given in Table 3, 
because they seem sufficient to prove the point. 

The sorghums in the first four series of analyses were grown in 
Minnesota, the Sudan grass in Oklahoma, and the two sorghums and 
the Johnson grass in' the last three series were grown in Uraguay, 
South America. The results of all these analyses are consistent, how- 
ever, in showing a practically uniform decrease in HCN content from 
the plant's beginning to its maturity. The confirmatory nature of all 
these analyses made by different investigators in widely separated re- 
gions leaves little to be desired in the way of proof regarding the 
comparative harmlessness of sorghum, Sudan grass, and Johnson grass 
when the plants have reached that stage of maturity in which seed is 
being formed. 



274 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 3. — The effect of maturity on the hydrocyanic-acid content of sorghum 

and Sudan grass. 



Crop. 


Age of 
plants. 


Height 
of plants. 


Stage of maturity. 


riL,iN in 
the whole 
plant. 


Reference 
No. 




Days. 


Inches. 




Percent. 






3 1 


T Q 

1 




0.083 


21, p. 181 




38 


28 




.032 






52 


39 











55 


42 




.007 






62 


61 




.002 




Do 


32 


26 




.064 


do 




39 


34 




.043 






45 


40 




.024 






62 


56 




.007 




Do 


32 


26 




.068 


do 




39 


38 




•045 






52 


42 




.02 1 






62 


59 









Do 


33 


14 




.114 


22, p. 263 




42 


18 




.028 






52 


28 




.019 






62 


38 




.009 






73 


56 




.002 






83 


67 




.001 






93 


78 




Trace 






2 2 


*5 


Very young 


•°579 


12, p. 448 




29 






.0274 






36 


— 




.0291 






43 


— 




.0094 




Sweet sorghum . . 


44 


8 


Very young 


.0293 


16 




02 


25 


Before heading 


.02 1 1 






99 


42 


Beginning to bloom 


.0057 






1X9 


46 


Blooming 


.0048 






135 


50 


Beginning to seed 


.0013 




' /lain -orgliuin . 


44 


16 


Very young 


.0192 


16 




62 


25 


Before heading 


.0176 






103 


42 


Beginning to bloom 


.0065 






120 


54 


Full bloom 


•0053 






135 


58 


Beginning to seed 


.0025 




Johnson grass. . . 


44 


8 


Before heading 


.0137 


16 




74 


13 


Beginning to bloom 


.0036 






94 


2 5 


Full bloom 


.0028 






log 


2 5 


Beginning to seed 


.0040 






130 


25 


Seed ripe 


.0028 





' The percentages of HCN arc all given on a dry-matter basis. 



RELATION M CUMAT1 10 TBI KYDEOCYANXC-ACID CONTENT OF PLANTS. 
It i| a matter of general knowledge among those who work with 
- crop that e;i es of prnssic acid poisoning are much less 



vixa;.l: prussic acid poisoning. 275 

common in the Gulf States than in States farther north. Very few 
complaints regarding srrghum poisoning are received from points in 
the United States south of 35 North latitude. This parallel marks 
the northern boundaries of South Carolina, Georgia, Alabama, and 
Mississippi, divides Arkansas practically in half, and passes thru or 
near the towns of Chickasha, Okla., Clarendon, Tex., Santa Rosa, 
N. Mex., Winslow, Ariz., and Mojave, Calif. 

The evidence concerning the comparative harmlessness of sorghum, 
Sudan grass, and Johnson grass in the region south of parallel 35 
is not quite so clear for the Southwestern States as it is for the region 
east of central Texas. This fact can perhaps be accounted for by the 
high altitudes and intense drouths of New Mexico, Arizona and south- 
ern California. Just why the sorghum plant and its related species 
should be so much more dangerous in Kansas, Nebraska, and eastern 
Colorado than in eastern Texas, Louisiana, Mississippi, Alabama, 
Georgia, South Carolina, and Florida has never been satisfactorily 
explained. The three crops are widely grown in both regions and 
acute dry periods are likewise common to both. 

Willaman and West (22) of the Minnesota station are the only 
investigators who have made a serious attempt to study the effect of 
climate on the hydrocyanic-acid content of sorghums, and unfortu- 
nately all their samples were obtained from points considerably north of 
the 35th parallel. They determined the HCN content of sorghum 
plants grown in Minnesota, South Dakota, Kansas and Utah. The 
spread was east and west rather than north and south. Their con- 
clusion from this work was that varietal differences were a larger 
factor in determining the amount of HCN in a sorghum plant than 
climate. It is impossible to accept this valuation of the climatic effect, 
however, until it is verified by comparing sorghum grow in Florida, 
Georgia, or some other Gulf State with plants grown in Minnesota, 
the Dakotas, Nebraska, or Kansas. 

An interesting side light on the problem is furnished by the anal- 
yses of some sorghums grown in Florida (4). Amber, one of the 
varieties used in the Minnesota experiments, when grown in Florida 
showed absolutely no prussic acid. In Minnesota this variety at the 
same height had 0.28 percent of prussic acid on a dry matter basis 
On the basis of fresh material, as used in Florida, Amber sorgo in 
Minnesota would have 0.0066 percent of prussic acid, a larger per- 
centage than any of the varieties included in the Florida analyses. 

There are at least three possible explanations of the apparently 
smaller number of cases of sorghum poisoning in the Southeastern 



2 7 6 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



States: (i) The quantity of glucoside stored by the plant may be 
less, (2) the enzyme which exists in the plan' and' is instrumental in 
breaking down the glucoside and liberating the prussic acid may be 
less active in these States, or (3) the HCN may occur in a more 
unstable form in sorghums grown in the North and West. The first 
of these explanations seems the more reasonable and further experi- 
ments are needed to prove or disprove the theory. 

RELATION OF THE HYDROCYANIC-ACID CONTENT OF SORGHUMS TO VARIETAL 

DIFFERENCES. 

Xo thoro study of this phase of sorghum poisoning has been made 
by chemists. As noted previously, Willaman and West (22, p. 272) 
concluded that "varietal difference is probably of more weight in 
determining the amount of hydrocyanic acid in sorghum than are 
conditions .of growth." 

The most impressive series of analyses yet published are those by 
Collison (4, p. 52). The material for these analyses was collected 
from plants 12 to 24 inches high and the amount of HCN varied from 
absolutely nothing in Amber sorgo to 0.0037 percent in Dwarf hegari. 
The results for the different varieties arranged in order of increasing 
amount of HCN are as follows : Amber sorgo o, Orange sorgo 
.0008, Dwarf milo .0016, Pink kafir .0016, Sunrise kafir .0018, Darso 
sorghum .0022, Dwarf kafir .0024, Shallu .0026, Brown kaoliang .0031, 
Feterita .0032, Blackhull kafir .0033, and Dwarf hegari .0037 percent: 
These percentages are all on the basis of fresh material. 

Chemical analyses, especially those of Collison, show a wide range 
of hydrocyanic-acid content in the ordinary varieties of sorghum. 
The probable error in such determinations is rather large no doubt 
and sufficient care is not always used to collect the material from 
plants of the same size or stage of maturity. 

SYMPTOMS OF PRUSSIC ACID POISONING. 

Prussic acid is a deadly poison and, when the quantity consumed is 
sufficiently large! death ensues very quickly, often within 15 minutes. 
When the amount taken into the system is not large enough to cause 
immediate death, the animal lives in many cases 4 or 5 hours, usually 
uft'ering acutely, and often recovers. The symptoms have been de- 
scribed in detail by Peters ( 14). 

A heifer wai turned into a field of BOrghum which had previously 
been responsible for the death of some cattle. Ten minutes after she 
had begun to eat the sorghum she dropped lo the ground and was 



vinall: prussic acid poisoning. 



277 



watched closely for 3.5 hours. It then became apparent that she 
would not recover and she was killed in order to make a post-mortem 
examination. When lying down the heifer's head was turned toward 
the abdomen as in the case of a horse having colic ; the muscles, es- 
pecially of the nose and head, twitched ; the pupils of the eyes were 
dilated and the eyes gave off a watery discharge ; the tongue was 
partially paralyzed and great quantities of saliva ran from the mouth; 
the limbs and ears were cold ; the pulse not perceptible ; and the 
mucous membrane of the rectum protruded with involuntary discharge 
of urine and feces. In the last stages the limbs were paralyzed and 
the animal was unconscious. The mucous membrane of the mouth 
was of a salmon color. 

The post-mortem examination revealed 1.5 pounds of sorghum 
leaves in the paunch. There was no sourness of the contents of the 
paunch and the mucous membrane of the intestines was normal as 
were all other internal conditions of the animal. A particular ex- 
amination of the pharynx, epiglottis, and esophagus showed that no 
leaves were lodged in any of these organs. Ten other post-mortems 
verified this freedom of the throat from obstructions, showing that 
death does not result from strangulation. The reports of other 
veterinarians agree in substance with this report of Peters, except 
that in some cases a slight bloating, which can not be relieved by 
puncturing the abdomen with a trochar, is said to accompany the 
poison effects. 

REMEDIES FOR PRUSSIC ACID POISONING. 

Numerous remedies for this poisoning have been proposed, but an 
effective safeguard against the poison is hard to devise because it is 
so quickly fatal. Glucose, dextrose, and other forms of sugar are 
known to act as antidotes to the poison. Avery found that twice the 
fatal dose of prussic acid could be given an animal without causing 
its death if the acid were accompanied by glucose ( 14) . These results 
of Avery's are so suggestive that they are repeated here in Table 4. 

Table 4. — Effect of glucose in lessening the poisonous action of prussic acid. 

Prussic acid administered. Results. 

0.2 gram Slight symptoms 

0.4 gram Animal very sick, but recovered 

0.8 gram in 15 grams glucose Very slight symptoms 

1.6 grams in 30 grams glucose Animal very sick, had severe convul- 
sions, but recovered 



278 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The prussic acid was administered to a barren heifer and sufficient 
time was allowed to elapse after each treatment for the animal to 
recover normal condition. 

Dowell in his work at the Oklahoma station (6, p. 178) added to the 
findings of Avery by showing that the presence of even 1 percent of 
dextrose or maltose in the digestion solution prevented the liberation 
of about three-fourths of the prussic acid from a sorghum sample. 
These sugars are both formed by the action of ptyalin on starches in 
the paunch of an animal and this furnishes a possible explanation of 
the fact that cattle which are being fed on corn can ordinarily pasture 
a sorghum field without injury. One way of reducing the danger of 
sorghum poisoning is to feed the animals some starchy concentrate 
like corn, kafir, milo, or feterita before turning them on sorghum 
pasture. Avery's recommendation of the use of glucose in the form 
of corn sirup and of milk as antidotes to the prussic acid, when it is 
possible to give them to the animal, is thus supported by experimental 
evidence. 

Haring of the California Agricultural Experiment Station (9) 
recommends an ever-ready antidote for prussic acid that is used in the 
cyanide plants of gold mines. It is prepared as follows : 

Bottle Xo. 1. — Select a quart bottle with a long neck suitable for drenching 
cattle. Place in this bottle one pint of water and one ounce of sodium carbon- 
ate (ordinary washing soda will do). Keep the bottle tightly corked. 

Bottle Xo. 2. — Place in this y 2 ounce of iron sulphate (copperas) dissolved 
in a pint of water. Keep tightly corked. 

When needed, pour the contents of bottle No. 2 into bottle No. I, shake, and 
administer immediately. A cow should receive a quart, and a sheep one-half 
pint of the mixture. This preparation can be made up in larger quantities if 
desired so that several animals may be treated at the same time. 

In addition to glucose, Francis of the Oklahoma station (8) lists 
the following remedies : A large dose of some quick acting purgative, 
such as mixture of Epsom salts and linseed oil; the inhalation of 
ammonia; peroxide of hydrogen introduced by means of a stomach 
tube; a combination of 1 to 2 drams of magnesia made into a smooth 
with water and poured down the animal's throat, this to be 
followed with 16 minims of a solution of iron chlorid and 1.5 grains 
of ferrous Mil fate dissolved in water. 

The disadvantage of most of the remedies recommended by Francis 
ifl that they require materials which, with the exception of the Epsom 
mid linseed oil, are not ordinarily kept on hand by the farmer. 4 
* Some <>{ the reincrlic advocated in farm papers are of interest because 

u nail) consist of materiali available in the farm home. One of these 
which seems to hare been born of actual experience is offered by Mrs. C. L. 



vixall: prussic acid POISONING. 



279 



Baldwin of Hitchcock County. Xebr.. in the Nebraska Farmer of March 24, 
1915, P- 384. I quote from this issue as follows : " We have a method for 
treating a cow that has been poisoned on cane which may be of benefit to some 
one. Place a teaspoonful of soda in a pint of vinegar that has been diluted 
until' it is suitable for a person to take, and drench the animal with this mix- 
ture while it is foaming. Half-pint doses, and from one to four of them, is 
all that we have ever used. Usually one is enough. A small lump of salt is 
placed in the animal's mouth to keep it open. By this treatment we have never 
lost a cow when we found them alive. We have saved them after they were 
unable to move." 

Any remedy to be effective must be available for instant use. 

LITERATURE CITED. 

1. Alway. F. J., and Trumbull. R. S. On the occurrence of prussic acid in 

sorghum and maize. In Xebr. Agr. Expt. Sta. 23d Ann. Rpt. (1909), pp. 
35-36. 1910. 

2. Balfour. Andrew. Cyanogenesis in Sorghum vulgare. First Rpt. Weil- 

come Research Lab. at the Gordon Memorial College, Khartoum, pp. 47- 
48. 1904. 

3. Bruxxich, J. C. Hydrocyanic acid in fodder-plants. In Tour. Chem. Soc. 

(London), v. 83, pt. 2, pp. 788-796. 1903. 

4. Collisox. S. E. Prussic acid in sorghum. Fla. Agr. Expt. Sta. Bui. 155. 

p. 52. 1919. 

5. Crawford, Albert C. The poisonous action of Johnson grass. U. S. Dept. 

Agr.. Bur. Plant Indus. Bui. 90, pt. IV, pp. 3-6- 1906. 

6. Dowell, C. T. Cyanogenesis in Andropogon sorghum. In Jour. Agr. Re- 

search, v. 16. no. 7. p. 180. 1919. 

7. Dunstan, W. R., and Hexry. T. A. Cyanogenesis in plants. Part II. The 

great millet (Sorghum rulgare). In Philosophical Trans. Royal Soc. 
London, ser. A, v. 199, pp. 399-410. 1902. Abs. in Proc. Roy. Soc. (Lon- 
don), v. 70, pp. 153-154- 1902- 

8. Fraxcis. C. K. The poisoning of live stock while feeding on plants of 

the sorghum group. Okla. Agr. Expt. Sta. Circ. of Information 38, pp. 
1-4. 191 5. 

9. Harixg. C. M. Precautions against poisoning by Johnson grass and other 

sorghums. Calif. Agr. Expt. Sta. unnumbered Circ, pp. 1-3. 1917- 

10. Hiltxer, R. S. The fatal effect of green sorghum. Xebr. Agr. Expt. Sta. 

Bui'. 63. pp. 71-84- 1900. 

11. Maxwell. W. Sorghum poisoning. Queensland Agr. Jour., v. 13. no. 

5. PP. 473-474- 1003. 

12. Mexaul. Paul, and Dowell, C. T. Cyanogenesis in Sudan grass: a modi- 

fication of the Francis-Connell method of determining hydrocyanic acid. 
In Jour. Agr. Research, v. 18. no. 8. pp. 447-450. 1920. 

13. Pease. Capt. H. T. Poisoning of cattle by Andropogon sorghum. In Jour. 

Comp. Med. and Vet. Arch . v. 18. pp. 679-683. 1897. 

14. Peters. A. T.. Slade. H. B.. and Avery. Samuel. Poisoning of cattle by 

common sorghum and kafir corn. Xebr. Agr. Expt. Sta. Bui. 77, pp. 1-16. 
1903. 



280 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



15. Ravenna, C, and Babini, V. On the presence of free hydrocyanic acid in 

plants, II. Atti R. Accad. Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5 ser., 
21, I, no. 8, pp. 540-544. 1912. 

16. Schroder, Johannes, and Dammann, Hans. Zur Kenntnis der aus ver- 

schiedenen Hirsearten Entwickelten Blausauremengen. In Chem. Ztg., 
Bd. 35, no. 155. p. I430-I437- 19". 

17. Slade, H. B. A study of the enzyms of green sorghum. In Nebr. Agr. 

Expt. Sta. 15th Ann. Rpt., pp. 55-62. 1902. 

18. . Prussic acid in sorghum. In Jour. Amer. Chem. Soc, v. 25, pp. 55- 

59- 1903. 

19. Willaman, J. J. The estimation of hydrocyanic acid and the probable 

form in which it occurs in Sorghum vulgare. In Jour. Biol. Chem., v. 
29, no. 1, pp. 25-36. 1917. 

20. — — . The effect of anesthetics and of frosting on the cyanogenetic com- 

pounds of Sorghum vulgare. In Jour. Biol. Chem., v. 29, no. i, pp. 37- 
45- 191 7- 

21. and West, R. M. Notes on the hydrocyanic-acid content of sorghum. 

/// Jour. Agr. Research, v. 4, no. 2, pp. 179-185. 1915. 

22. . Effect of climatic factors on the hydrocyanic acid content of sor- 
ghum. /;/ Jour. Agr. Research, v. 6, no. 7, pp. 261-272. 1916. 



CROSS-POLLINATION OF MILO IN ADJOINING ROWS. 1 

John B. Sieglinger. 2 

In 1 919 Karper and Conner 3 published data showing the amount of 
natural cross-pollination between white and yellow milo. The two 
varieties were in bloom at the same time, and each white milo plant 
was surrounded by plants of yellow milo. Under these conditions, 
6.18 percent of cross-pollination occurred. 

To determine the amount of cross-pollination occurring in the 
direction of the prevailing wind between adjoining rows of the same 
height and blooming at the same time, Standard yellow milo, C. I 
No. 234, and Standard white milo, C. I. No. 352, were grown in 
adjoining plats on the Woodward Field Station in 1919. The yellow 
milo was BOUtfc of the white milo in rows running cast and west, the 
prevailing wind being from south to north. These two varieties differ 

1 Contribut ion from the Office of Cereal Investigations, Bureau of Plant In- 
dustry, U. S. Department of Agriculture, Washington, D. C. Received for 
; nhlii ation February II, 1921. 

tanl RgronOOlift in charge Of cereal experiments on the Woodward 
Field Station, Woodward, Okla. 

k. I- . and Conner, A. H. Natural cross-pollination in milo. In 
I*. nr. Am*r. Soc. Agron., v. 11, no. 6, pp. 257-259. 1919. 



sieglinger: cross-pollination of milo. 



281 



only in seed color. The date of first heading was recorded as August 
4 for both varieties and all plants were headed August 22. The 
date of first heading is recorded as the date when the first heads are 
fully exserted from the sheath, and the date of full heading as the 
date when all the main heads are exserted. In the period from 
August 4 to 22 most of the blooming of the milo occurred, i.e., when 
the first heads emerged from the boot the flowers at the tip or upper 
end were starting to bloom and by the time the main heads had fully 
appeared blooming was about completed. To meet the possible ob- 
jection that blooming was not completed at this time, wind velocity 
and direction are shown in Table 1 for a period including seven days 
after heading ended. 



Table i. — Average hourly velocity and direction of wind at Woodward, Okla., 
during the period from August 4 to 29, 1920. 



Date, 


Average velocity, 


Direction 


Date, 


Average velocity, 


Direction 


August. 


miles per hour. 


at 8 a.m. 


August. 


miles per hour. 


at 8 a.m. 


4 


9.4 


S.W. 


17 


5-2 


S.E. 


5 


7.6 


S.W. 


18 


3-7 


N.W. 


6 


5-6 


S.W. 


19 


6.1 


S.W. 


7 


3-5 


S. 


20 


5-i 


S.W. 


8 


1.6 


S.E. 


21 


5-6 


S.W. 


9 


3-1 


S. 


22 


6.4 


S.W. 


10 


5-3 


S. 


23 


6-3 


S.W. 


11 


8.1 


S.W. 


24 


4.4 


s. 


12 


7-i 


S.W. 


25 


4.0 


S.W. 


13 


4.8 


N.E. 


26 


7.6 


S.W. 


14 


11.8 


S.E. 


27 


9.2 


w. 


15 


4.6 


S.W. 


28 


9.0 


S.W. 


16 


3-5 


N.E. 


29 


6-5 


S.W. 


Table 


I shows that 


the wind 


was from 


the south, southwest, or 



southeast practically thruout the blooming period. 

All of the main heads o,n the south row of white milo were saved 
for use in this experiment. This row of white milo was pure in 1919, 
as not a single hybrid plant appeared that year. Due to a shortage of 
land, only 12 heads were sown in separate rows in the field in 1920. 
Not all the seed from any one head was required to sow one of the 
rows, which varied from 300 to 320 yards in length. The stand 
obtained was fair, tho it was not uniform in the different rows. This 
variation may have been due in part to differences in germination, 
tho injury by moles was also a factor. 

When the milo was ripe counts were made of the total number of 
plants in each row and of the number of plants producing yellow- 
seeded heads. The data obtained are shown in Table 2. 



282 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 2. — Total number of plants, number of plants with yellow seeds, and 
percentage of cross-pollination in 12 rows of white milo. 



Row No. 


lotal number 
of plants. 


Number of yellow- 
seeded plants. 


Percentage of 
cross-pollination. a 


1 


483 


23 


4.76 


2 


459 


12 


2.61 


3 


437 


28 


6.41 


4 


415 


22 


5-30 


5 


432 


37 


8.56 


6 


355 


16 


4-51 


7 


401 


27 


6-73 


8 


536 


45 


8.40 


9 


413 


12 


2.91 


10 


552 


15 


2.72 


11 


295 


23 


7.80 


12 


347 


16 


4.61 


Total 


5-125 


276 


5-38 



Except in row 5, all the hybrids were yellow-seeded. In row 5 there were 
4 plants which bore light brown seed. These are not included in the above 
figures. If these are included, the percentage of cross-fertilization for row 5 
would be 9.49 instead of 8.56, changing the average of all rows from 5.38 to 
5.46 per cent. 

W hile the numbers here reported are not large enough to be 
conclusive, they give an indication of the amount of cross-pollination 
between two varieties of sorghum of the same height and blooming 
at the same time, when grown in adjoining rows. The percentage 
shown in Table 2, 5.38 percent, is slightly less than that reported by 
Karper and Conner, 6.18 percent, from plants of white milo sur- 
rounded by yellow milo. 

AGRONOMIC AFFAIRS. 

ANNUAL MEETING OF THE SOCIETY. 

The fourteenth annual meeting of the American Society of Agron- 
omy will be held at New Orleans, La., on November 7 and 8, im- 
mediately preceding the annual sessions of the Association of Land- 
firanl 1 As usual, many other agricultural meetings will be 

held during the week of the college and station meeting. The pro- 
gram will consist of a 8ymp081Um on teaching farm crops courses, 

under the direction of Prof, L. -V Call, and a Bymposium on nitrogen 

ted by Dr. J. G. Lipman, There will also be a session at which 

eou papen w ill be presented, while the meeting on Monday 

' . <>\ cinbrr 7, will be ri joint session with the Society for the 



AGRONOMIC AFFAIRS. 



283 



Promotion of Agricultural Science, at which the presidents of the 
two societies will deliver their presidential addresses. Headquarters 
will be in Hotel Grunewaldt. 

BOOK REVIEW. 

The Chemistry of Plant Life. By Roscoe W. Thatcher. Nezv 
York: McGraz^-Hill Book Co., 1921, pp. 268. — We now have avail- 
able in English a number of excellent text books on physiological 
chemistry or biochemistry, written primarily from the standpoint of 
animal life. Altho there is much of the chemical phenomena in life 
common to both animals and plants, there is an important biochem- 
istry peculiar to plant life. The recent appearance in English of 
two books on this phase of biochemistry is evidence of the growing 
interest in the subject. One is by Onslow of England on " Practical 
Plant Biochemistry " and the other, the more recent one, by Dean 
Thatcher on "The Chemistry of Plant Life," the subject of this 
review. The author states in the preface that he has had in mind a 
two-fold purpose in the preparation of the book. " First, it is hoped 
that it may serve as a text or reference book for collegiate students of 
plant science who are seeking a proper foundation upon which to 
build a scientific knowledge of how plants grow. Second, the pur- 
pose of the writer will not have been fully accomplished unless the 
book shall serve also as a stimulus to further study in a fascinating 
field." 

The material presented in the book was developed from a series of 
lecture notes which were used in connection with a course in " Phyto- 
chemistry " offered by the author for several years to the students of 
the Plant Science group of the University of Minnesota. The 
author's extensive experience and knowledge in the field places the 
stamp of authority on the material presented in the book. 

It is assumed that the students who will use this book will have had 
some previous training in elementary inorganic and organic chemistry, 
altho an extensive course in organic chemistry is not requisite to the 
understanding of the chemistry of the different groups of plant com- 
pounds presented. 

The introduction gives a brief historical resume of the revolution- 
ary changes in the conceptions which men have held concerning the 
nature of plant and animal growth. This is followed by a discussion 
of the place and importance of phytochemistry in the field of biologi- 
cal science and of the similarities and antitheses in the chemical prin- 
ciples involved in the biochemistry of plants and animals. The 
introduction closes with the statement that the object of the study of 
the chemistry of plant growth is to acquire a knowledge of the consti- 
tution of the compounds involved and of the conditions under which 
they will undergo the chemical changes which, taken together, consti- 
tute the vital processes of the cell protoplasm. 



28 4 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The first chapter deals with Plant Nutrients. The usual confusion 
in the use of the term plant food is avoided by designating as synergic 
foods those forms which supply both material and energy, while those 
which contain no potential energy are designated as anergic foods. 
The up-to-date discussion of the role in plant growth of plant-food 
elements from the soil should be of special interest to agronomists. 
The simple explanation of the mechanism by which these food ele- 
ments enter the plant from the soil and " circulate" thru the plant is 
hardly adequate for a correct understanding of these processes. The 
chapter is concluded with a brief discussion of inorganic plant toxins 
and stimulants. 

The following twelve chapters are devoted to the organic com- 
pounds of plants and to types of chemical changes involved in plant 
growth. The synthetic activities are given much greater emphasis 
than the destructive processes of respiration. The organic com- 
pounds are presented and discussed under the following groups: 
Carbohydrates and their derivatives, the glucosides and the tannins ; 
the fats and waxes; the essential oils and resins; organic acids and 
their salts ; the proteins ; the vegetable bases and alkaloids ; the 
pigments. The final paragraphs under each group take up the physio- 
logical uses and biological significance of the compounds considered. 
Physiological uses refer to the plant's own internal needs, while the 
phrase biological significance refers to the relation of the plant to 
other living organisms or the relation of certain compounds to the 
survival of the species in the competitive struggle for existence. The 
treatment of the polysaccharides is unusual. The author states that 
they are known under the general name of " starches," but technically 
known as " hexosans." The gums, pectins, and celluloses are not 
classed with the carbohydrates but treated as a distinct group of com- 
pounds. The discussion of the pentosans illustrates the present con- 
fusion and difficulties involved in the classification and general 
description of the compounds which, on hydrolysis, give five carbon 
sugars. 

The chapter on pigments is especially valuable since the important 
discoveries resulting from the classical researches in this difficult 
field by Willstatter and his collaborators as well as those of Wheldale 
are concisely assembled. 

One chapter is devoted to each of the following topics: Enzymes 
and their action; the colloidal condition; the physical chemistry of 
protoplasm; hormones, auximones, vitamines, and toxins. The last 
< hapter of this scries is based upon investigations carried on within 
very recent year- and Btill in progress, SO no definite conclusions are 
el po^ible. However, the discussion is timely as evidence is 
. i iinnilating which points to the importance of certain substances in 
plant growth not generally recognized in our present theories. The 
onclnded with a very interesting chapter on the difficult sub- 
ject of adaptations. 

All those interested in plant biochemistry will be grateful for this 
iish text on the subject. — C. O. Appleman. 



AGRONOMIC AFFAIRS. 



285 



NOTES AND NEWS. 

L. C. Aicher, for the past ten years superintendent of the Aber- 
deen (Idaho) substation, became superintendent of the Hays Branch 
Station, Hays, Kans., on October I. 

Dr. Elmer D. Ball, assistant secretary of agriculture since June, 
1920, has been made director of scientific work in the United States 
Department of Agriculture, effective October 1. This is a new posi- 
tion provided for in the appropriation act for the department for the 
current fiscal year. Provision was also made for a director of regu- 
latory work, but this official has not yet been named. 

Dr. John Lee Coulter, dean of the West Virginia college of 
agriculture and director of the experiment station, has been elected 
president of the North Dakota Agricultural College. 

Dr. E. P. Deatrick, formerly instructor in the department of soil 
technology at Cornell University, is now associate professor of soils 
and head of the soils department at the West Virginia college of 
agriculture. 

W. J. Green, until recently superintendent of extension on the 
Island of Guam, is now extension agronomist at the Oklahoma college. 

Dr. Frank S. Harris, director of the Utah station, has been elected 
to the presidency of Brigham Young University at Provo, Utah. He 
has been succeeded as director by William Peterson, formerly geologist 
in the Utah Agricultural College. 

H. D. Hughes, professor of farm crops in the Iowa college, has 
been granted a year's leave of absence and is now associated with 
commercial growers of annual white sweet clover seed in Alabama. 

Irving S. Jensen, a 1918 graduate of the Utah college, is now 
instructor in agronomy in Montana State College. 

H. L. Kent, superintendent of the Hays (Kans.) branch station, has 
been elected to the presidency of New Mexico State College. 

A. C. Kuenning, formerly county agent in Dickey Co., N. Dak., is 
now superintendent of the Williston (N. Dak.) substation. 

Clyde McKee, associate professor of farm crops in Iowa, has been 
elected agronomist of the Montana station and head of the department 
of agronomy in Montana State College. 



286 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



G. P. McRostie, recently a graduate student at Cornell University, 
is now assistant professor of cereal husbandry in Macdonald College, 
Quebec. 

Paul C. Mangelsdorf, a recent graduate of the Kansas college, is 
now with the New Haven (Conn.) station. 

E. G. Montgomery, formerly in charge of foreign marketing investi- 
gations for the Department of Agriculture, is now chief of the food- 
stuffs division of the Bureau of Foreign Commerce, Department of 
Commerce. 

E. O. Pollock, formerly of the farm crops department of the 
University of Missouri, is now with the Porto Rico college of 
agriculture. 

C. W. Pugsley, editor of the Nebraska Farmer and formerly direc- 
tor of extension in the Nebraska college of agriculture, became 
assistant secretary of the Federal Department of Agriculture on 
October I. 

Karl S. Quisenberry, recently nursery foreman for the farm crops 
section of the Kansas station, is now associated with the West 
Virginia college of agriculture. 

W. H. Stevenson, head of the department of soils and crops at the 
Iowa college and vice-director of the station, has been given a year's 
leave of absence to become representative of the United States on the 
permanent council of the International Institute of Agriculture at 
Rome. 

Dr. W illiam E. Stone, president of Purdue University since 1900, 
fell from a cliff near the summit of Mt. Eanon, Alberta, July 16 and 
was instantly killed. 

II. C. Taylor, chief of the Federal office of farm management, 
-uecccded George Livingston as chief of the Bureau of Markets on 
July I, on which date it was combined with the Bureau of Crop 
Estimates. 

Dr. N. I. Vavilov, director of the Russian Bureau of Applied 
Botany and Plant Industry, made an extended tonr of the United 
State- during August and September. 

G F, Warren, professor of Farm management at Cornel] University, 

has been granted leave Of absence tO February 1, \<)22, to become con- 
sulting specialist in the reorganization of the Federal Bureau of 
Markets and ( rop Estimates. 



A G RO N OM IC A F F AIRS. 



287 



John B. Wentz, formerly professor of farm crops in the Maryland 
college, is now associate professor of farm crops in the Iowa college. 

The Board of Trustees of Ohio State University has authorized the 
establishment, within the College of Agriculture, of The Plant Insti- 
tute of Ohio State University. All members of the staff of the 
college interested in plant studies may be members, and all graduate 
students doing their major work with plants are associate members. 
The Institute will conduct a seminar, review the work of its graduate 
students, and encourage research, especially the study of such prob- 
lems as require cooperation. The departments of the college chiefly 
concerned are botany, horticulture, farm crops, agricultural chemistry, 
and soils. Thomas G. Phillips is secretary of the institute. 

An Italian agronomic society (Societa Agronomica Italiana) has 
been organized, with headquarters at Via dei Crescenzi No. 26, Rome, 
" with the idea of uniting all branches of science in any way connected 
with agriculture." Senator B. Grassi, director- of the Institute of 
Anatomy, University of Rome, is president of the society. Among 
the important problems which are being studied by the society are 
the best means of utilizing poor and arid lands, with a special study 
of drouth resistance ; influence of physical and meteorological factors 
on the yield of wheat in southern districts ; means of combating in- 
sects injurious to the olive ; the utilization of the abundant leucite 
deposits for the production of potash manures ; and the causes of the 
root rot of citrus fruits. 

The first report of the council of the National Institute of Agricul- 
tural Botany of Great Britain has been received. This institute was 
organized in the winter of 1917-18 as an outgrowth of the wartime 
realization of Britain's need for greater food production. The first 
meeting of the council was held January 21, 1919. Sir A. Daniel 
Hall, Sir Lawrence Weaver, and Prof. R. H. Biffen are vice-presi- 
dents of the Institute and Sir Lawrence Weaver is chairman of the 
council. W. H. Parker is director of the Institute and chairman of 
its committee on field trials. Chairmen of other committees are 
Prof. R. G. Stapledon, grasses and clovers ; Sir Lawrence Weaver, 
potatoes ; E. S. Beaven, cereals ; and R. N. Salaman, potato syno- 
nyms. The institute has headquarters and trial grounds at Cam- 
bridge, a 354-acre farm in Huntingdonshire, and a 39-acre potato 
testing station in Lancashire. One of the important policies of the 
institute is the rapid increase and dissemination of improved varieties 
of agricultural plants. 



288 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



CONFERENCE ON FARM CROPS TEACHING. 

Following is the program of the conference, on collegiate teaching 
of farm crops, which was held at the University of Illinois, Urbana, 
111., August 4 and 5. 

Thursday, August 4, A.M. 

The Kind of Teaching in Farm Crops Suited to Agicultural Students, Dean 
Eugene Davenport, University of Illinois. 

In what 3 r ear should the elementary course in farm crops be given and what 
should be its position in the curriculum with reference to the basic sciences? 
Discussion led by Prof. E. S. Kinney, University of Kentucky. 

What should be the nature of the class work in the elementary course in 
crops, prerequisites and* content? Discussion led by Prof. M. L. Fisher, Pur- 
due University. 

2 P.M. 

What should be the primary object of the elementary course in farm crops: 
(a) To give an essential instruction in the practical production of crops which 
would be more or less complete in itself, or (b) to lay the foundation for fur- 
ther studies of the subject? Discussion led by Prof. W. C. Etheridge, Uni- 
versity of Missouri. 

What part of the elementary course in farm crops should be devoted to lab- 
oratory work and what should be the nature of this work? Discussion led by 
Prof. J. W. Zahnley, Kansas State Agr. College. 

The relation of the crops courses taught in vocational schools to the standard 
of the elementary course in Farm Crops. Discussion led by Dr. W. L. Burh- 
son, University of Illinois. 

Friday, August 5, 9 A.M. 

The relation of plant physiology and courses in botany to farm crqps 
teaching. Discussion led by Prof. J. F. Cox, Michigan Agri. College. 

The advanced undergraduate courses in farm crops — their nature and gen- 
eral characteristics. Discussion led by Prof. J. B. Park, Ohio State University. 

Would it be advisable to hold inter-collegiate grain judging contests? Dis- 
CUSSiofl led by Prof. Clyde McKce, Iowa State College. 

2 P.M. 

Reports of committees. 

An inspection of the work in agronomy at the University of Illinois. 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. November, 1921. No. 8 



METHODS OF APPLYING INOCULATED SOIL TO THE SEED 
OF LEGUMINOUS CROPS. 1 

A. C. Arxy and F. W, McGinnis, 2 
Introduction. 

The beneficial interrelationship between leguminous crops and cer- 
tain bacteria in utilizing the free nitrogen of the air has been known 
since 1886. Since that date various practices in securing inoculation 
for leguminous crops have been worked out. It has been found that 
the particular bacteria needed for a certain group of crops may be 
isolated and increased as pure cultures and so distributed. Various 
pure cultures have been put out from time to time. The earlier and 
some of the later attempts in the preparation of pure cultures have not 
always been entirely satisfactory and hence the soil transfer method 
has been used very widely. This consists of transferring to the new 
field and scattering thoroly from 100 to 300 or more pounds of soil 
per acre from a nearby field which has grown a legume and which is 
known to have the necessary bacteria present. 

Transfer of this- amount of soil for each acre in which the plants 
are to be supplied with bacteria for short distances involves only the 
labor of hauling and scattering, which is considerable, while for greater 
distances the additional expense of freight must be considered. 

To reduce the expense of the soil transfer method the practice of 

1 Published with the approval of the Director as Paper 223 of the Journal 
Series of the Minnesota Agricultural Experiment Station, University Farm, St. 
Paul, Minn. Received for publication December 13, 1920. 

2 Head of section of farm crops and assistant professor of farm crops, re- 
spectively, in the Division of Agronomy and Farm Management, Department 
of Agriculture, University of Minnesota. 

289 



290 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



sticking to the seed a small quantity of soil containing the necessary 
organism has been recommended and used widely, apparently without 
experimental evidence as to the efficiency of the practice as compared 
with transferring larger quantities of soil. This method consists of 
moistening the seeds with a weak glue solution and then dusting on a 
bushel of seed approximately a pound of finely sifted air-dry soil 
known to contain the desired bacteria. This dries the seed so that it 
is ready for immediate use. The results secured from the use of this 
method have been quite variable. 

In Minnesota, with the exception of certain areas, alfalfa, sweet 
clover, and soybeans have not been grown sufficiently up to the present 
time to eliminate the necessity for supplying the proper bacteria to 
new sowings. Results from the use of commercial inoculants had not 
been satisfactory. To obviate handling large amounts of soil the glue 
method was used and results were non-uniform. Therefore, it was 
determined to secure comparative data on various practices in connec- 
tion with the inoculation of these leguminous crops. The various 
phases may be outlined as follows : 

1. Comparison of amounts of soil adhering to a bushel of seed, using water 

only and various concentrations of glue and sugar. 

2. Comparison of thoroness of inoculation on different soils where the seed 

was treated in different ways. 

3. Comparison of value of old and fresh inoculating material and the effect of 

exposure of the treated seed to the sunlight. 

Review of Literature. 

The thoroness of inoculation of leguminous plants as indicated by 
the appearance of nodules on their roots and color and vigor as com- 
pared with uninoculated plants grown under the same conditions de- 
pends upon several factors. 

The number of vigorous bacteria per seed sown does not appear to 
have much influence, according to Fellers (4)*, within certain rather 
wide limits. However, in another experiment the addition of more 
bacteria than were carried on the seed gave additional numbers of 

nodules per plant with soybeans and alfalfa. The same author states 
that where the number of cells in commercial cultures ran below 
1 ,000,000 per eubi< centimeter the results were not n snail v satisfactory. 

' " ■ '-'"d ' i"inri 1 u) used both a half and i pound of soil per 
Bi re for inoculating various leguminous seeds in comparison with sev- 
eral Commercial inoculants. The amounts used gave satisfactory re- 
sults with sweet clover, but for cowpeas, soybeans, and hairy vetch the 

K' f« rru 1 1 |f, " Literature cited," p.itfc 303. 



ARNY & M'GINNIS : INOCULATION OF LEGUMES. 29I 

inoculation was practically nil. Double the amount of commercial 
inoculant used in the first experiment gave in a succeeding experiment 
with soybeans 75 percent inoculation as compared with 20 percent for 
the check. From this work the authors conclude that larger quantities 
of both commercial cultures and soil than were used would be neces- 
sary to give satisfactory inoculation. 

An examination of a number of commercial cultures by Temple (13) 
showed for the most part sufficient numbers of bacteria in the amount 
put up for a given area to bring about satisfactory inoculation. 

Hopkins (6) advised gathering soil to a depth of from 3 to 4 inches 
from fields growing the same kind of legume crop, the plants of which 
upon examination are found to have nodules on their roots, and scat- 
tering this broadcast at the rate of a few hundred pounds per acre at 
the time the new field is to be seeded. Later (7) the following direc- 
tions were given: "Moisten the seed with a 10 percent glue solution 
(1 pound of furniture glue to 1 gallon of water) and immediately sift 
over them sufficient dry pulverized infected soil to absorb all of the 
moisture, thus furnishing a coating of infected soil for every seed." 

Satisfactory results with commercial inoculation, but still better from 
the application of 200 pounds of soil per acre from an old alfalfa field, 
are reported by Arny and Thatcher (1). The numbers of bacteria 
supplied by each of the two methods were not checked. 

There appears to be a difference in the ease of inoculation of the 
different crops. Noyes and Cromer (12) found soybeans, cowpeas, 
and hairy vetch free from nodules under the same conditions that gave 
good inoculation of sweet clover. 

Fellers (3) found more commercial cultures for soybeans ineffective 
than for other crops and recommends the soil transfer method for this 
crop unless the commercial cultures are known to be of good quality. 

Moisture conditions in the soil influence the number of nodules pro- 
duced on plants. A water content in the soil of 75 percent is reported 
by Wilson (14) as giving more nodules per 100 plants than a water 
content of 65 percent and considerably more than a water content of 
25 percent. 

Noyes and Cromer (12) secured a higher percentage of inoculation 
on brown silt loam than on sand for both the checks and the plats 
receiving barnyard manure. The presence of various substances in 
the soil may affect the percentage of inoculation, nitrate of soda tending 
to reduce it. 

Fred and Graul (5) found that alfalfa responded to inoculation to 
a greater extent on Plain field sand than on Colby silt loam. Clover 
responded to treatment only on the Plainfield sand. 



2Q- JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Nitrates and sulfates applied in experiments made by Wilson (14) 
in amounts which inhibited nodule formation did not reduce the ability 
of these bacteria to produce nodules when brought under suitable con- 
ditions. Nitrogenous compounds were found to be local in character 
in their effect on inhibiting nodule formation. Carbon-containing 
compounds in soil cultures stimulated nodule formation. Mention is 
also made that the composition of the soil solution is a factor in con- 
trolling nodule formation. 

Nobbe and Richter (10) found that where there was considerable 
soluble nitrogen in the soil the amount of atmospheric nitrogen fixed by 
bacteria working in connection with leguminous plants was less than in 
soils with less nitrogen available. 

Moore (9) states that various external conditions such as heat, 
moisture, alkalinity, amount of nitrogen in soil, etc., may have a direct 
influence on nodule formation. 

Fellers (4) treated alfalfa seeds with gum tragacanth and inoculated 
them with nodule infusion. He concludes from the experimental data 
that the gum tragacanth probably aids to some extent in protecting the 
bacteria, but not enough to justify its use. 

Magoon and Dana (8) state that they can see no advantage from 
the use of glue used to cause soil particles to adhere to the seed. They 
suggest that, since glue is usually heavily infested with bacteria of 
various kinds, antagonism of types may cause destruction of the 
nitrogen-fixing forms. 

The effect of exposure of the seed after treatment or of storing it 
for a time previous*to sowing has been considered by several workers. 
Chester (2) concludes that the legume bacteria perish very rapidly 
when (hied on the seed. Fellers (4) found the greatest decrease in 
numbers of bacteria on seeds during the first few hours after inocula- 
tion, with a relatively slow and uniform decrease up to six months. 
Prom the results secured the author concludes that storing the seed 
Several days to a month after applying the tnoculant should do no 
great harm. The seeds would necessarily need to be stored in a suit- 
able place. 

Temple | [3) stored inoculated field pea seed in a loosely stoppered 
bottle and made sowings at intervals of 30 days. Nodules were se- 
cured Otl all sowings np to the fifth month. 

Nobles ( 1 1 ) exposed small amounts of soil containing nitrogen- 
bacteria to the lUnlighl for different periods. At the end of 15 
minutes' exposure only [8.9 percent in the sandy soil and 46.3 percent 
mi a COmpOSt remained alive. \ fter 7 hours' exposure only 0.5 percent 
was found alive. 



ARNY & M GINNIS: INOCULATION OF LEGUMES. 



293 



Material and Methods. 

In all of the different trials reported seed handled and stored in the 
ordinary manner was used without sterilization. Seed of the Chestnut 
soybean, Grimm and common alfalfa, and biennial white sweet clover 
were used. 

Dry furniture glue was used in making up the solutions of this 
material. The sugar solution was used to avoid any substances in the 
glue which might be undesirable. Granulated white sugar was used. 
During ordinary times the small amounts needed would not be pro- 
hibitive if results warranted its use. 

Tests were made both in the greenhouse and in the field. A white 
sand sterilized by steam was used in gallon jars in the greenhouse tests 
only. Here the required nutrients were supplied. A sandy soil from 
Coon Creek, in Anoka County, was sterilized and used in 6-inch pots 
in the greenhouse, but the growth of the soybean plants was so ab- 
normal that the tests were considered unsatisfactory. Tests were 
made using the black loam from University Farm without sterilization 
in the greenhouse. The sandy soil at Coon Creek is decidedly acid in 
reaction and the black loam at University Farm slightly so. Previous 
tests had indicated that these soils were practically free from the bac- 
teria which work in symbiotic relationship with the crops used. 

The soil used for inoculating purposes was taken from fields on 
University Farm which had recently produced crops, the plants of 
which were well inoculated, as indicated by an abundance of nodules 
on their roots. It was dried without exposure to sunlight and put 
thru a very fine sieve. When used it was very much like fine road 
dust. The seed was moistened, spread out, and the fine soil dusted 
over it. The seed was used immediately unless otherwise indicated. 
The commercial inoculant used was a commercial culture. 

Little difficulty was experienced in the majority of instances in dis- 
tinguishing, by the location and number of nodules on the roots, the 
difference between the chance inoculation of the checks where this 
occurred from the condition where the bacteria were supplied. 

In the greenhouse tests the plants were thinned to ten per jar or pot. 
In the field, seed given the various treatments was sown in replicate 
rod rows 1 foot apart. 

Unless otherwise indicated in the field trials, 50 soybean plants and 
100 alfalfa plants were dug, the moist soil carefully removed, and the 
number of nodules on each plant counted. In all probability some of 
the nodules were removed with the soil and therefore were not in- 
cluded in the count. 



294 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Interpretation of Results. 
In order to secure data which might aid in the interpretation of the 
results of the experiments, 200 6-inch pots were filled with black loam 
soil from University Farm, placed in the greenhouse, and sown with 
alfalfa seed treated in four ways. There were 50 pots each sown with 
seed to which inoculated soil was made to adhere with 20 percent glue 
and sugar solutions, and a like number each with the same weight of 
inoculated soil applied as seed used and with a commercial culture 
applied to the seed in the usual way. The seeding was done on May 7, 
1920. When the plants were large enough, the number in each pot 
was uniformly reduced to ten. On August 11 the contents of each 
pot was turned out, the roots washed from the soil with a gentle stream 
of water, and the number of nodules per 10 plants counted, with the 
results shown in Table 1. 



Table i. — Number of nodules per pot of ten plants, number of nodules per 
plant and the variation in the number of nodules per plant grown in 
the greenhouse from alfalfa seed variously treated. 







Variation in 


Average 


Average 


Method of 


Number 


number of 


number of 


number of 


inoculation. 


of pots. 


nodules per 


nodules 


nodules 






50 pots. 


per pot. 


per plant. 


Glue solution and soil 


50 


12.2 


46.7 


4.67 


Sugar solution and soil 


50 


18.8 


47-3 


4-73 


Same weight of soil as seed 


50 


18.8 


50.9 


5 09 


Commercial culture 


50 


41.6 


102.0 


10.20 


Average 


50 


22.85 


61.76 


6.176 



Considering all the pots in the test, the average number of nodules 
per pol ia 61.76. The percentage of variation for the test was found 
by the pairing method to be [7.29. Considering 50 pots of each treat- 
ment, the variation in number of nodules per pot is 1. 5106. Accepting 
JO to 1 as the lowed odds which may be considered reasonably certain, 
the least significant difference between the average number of nodules 
iii the potfl of any two treatments is 574. Using this figure in a broad 
way in the interpretation of the results of this test, the glue, sugar, and 
lOll methods may be considered equally good. Likewise, the commer- 
l ial I lllture ma) be considered as giving better results than any one of 

the other methods. The figure, 5.74, derived from the results of this 

trial, where B comparatively large number was considered, may be used 

toadi antage In the interpretation of the results in the main experiments. 



ARXY & M'GINNIS : INOCULATION OF LEGUMES. 



295 



The Glue Method ox Trial. 
To try out the efficiency of the various methods commonly used in 
inoculating seed, 5-percent solutions of glue and sugar were made up 
and soil made to adhere to seed by their use. Likewise, seed was 
treated with a commercial culture in the ordinary way. This variously 
treated seed, together with seed to which the same weight of soil was 
added at seeding time, was sown in five pots each of University Farm 
soil in the greenhouse on June 7, 1919. The crop used was soybeans. 
On July 26 five additional pots of each treatment were made up for 
both soybeans and alfalfa. The plants were thinned to 10 per pot 
and on the dates indicated the contents of each pot were turned out 
and the roots washed free from soil by using water. The results are 
given in Table 2 in the form of number of nodules per plant. 

Table 2. — Number of nodules per plant for soybeans and alfalfa in greenhouse 

trials from seed variously inoculated. 

First trial, soy- Second trial, soybeans 
beans only, sown and alfalfa, sown 

Crop and method of inoculation. June 7, read Aug. 28. July 26, read Sept. 25. 

Soybeans : 

Xo inoculation 4.8 0.35 

Glue solution and soil 6.1 4.80 

Sugar solution and soil 8.1 4.20 

Equal weights of soil and seed 20.8 6.90 

A commercial culture 10.2 12.00 

Alfalfa : 

Xo inoculation 1.70 

Glue solution and soil 10.70 

Sugar solution and soil 10.60 

Equal ^veights of soil and seed 17.60 

A commercial culture 25.00 

In the greenhouse tests with soybeans the controls showed an abnor- 
mally high inoculation. This probably makes the test of little or no 
value. In the second test a commercial culture was the most effective. 

With the alfalfa both the glue and sugar solutions with soil gave 
satisfactory inoculation. However, where soil equal in weight to the 
seed and the commercial culture were used decidedly higher numbers 
of nodules per plant were secured. 

In addition to these seedings in the greenhouse, the work was ex- 
tended to the field, where four regularly distributed rod rows i foot 
apart were sown at University Farm and on the peat at Coon Creek. 
On the dates indicated in Table 3, 50 plants from each row of soybeans 
and 100 plants from each row of alfalfa and sweet clover were care- 
fully dug and read, the results being given in percentage of plants 



296 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



inoculated.- Any plant bearing one or more nodules was read as inocu- 
lated. It is appreciated that some nodules may have been lost because 
of the technique which was necessarily followed in the reading. 

Table 3. — Average percentage inoculation of soybeans, alfalfa, and szveet clover 
plants in Held trials on University Farm and on Coon Creek peat from 
seed sown August 7, 1919, as shown by readings on the dates indicated: 



Location and dates of readings. 



_ - . . 
Crop and method 01 inoculation. 


University Farm. 


Coon Creek peat. 


Sept. 24* 






oepu. 


Oct. 10. 




Percent. 


Percent. 


Percent. 


Percent. 


Percent. 


Soybeans: 












No inoculation 


1.6 








1.0 





Glue solution and soil 


16.5 


31-3 


4-5 


11. 7 


15-5 


Sugar solution and soil 


28.0 


28.0 


19.6 


22.0 


46.7 


Same weight of soil as seed . . . 


80.5 


80.5 


68.7 


93-0 


81.7 




89.0 


89.0 


93-9 


95-7 


97-3 


Alfalfa : 














2.5 


5-5 





2.0 


3-0 


Glue solution and soil 


10. 


19-0 


11. 7 


18.3 


25.0 


Sugar solution and soil 


10. 


10. 


13.0 


15.0 


26.0 


Same weight of soil as seed . . . 


11.3 


27.0 


33-2 


36.3 


73-3 


A commercial culture 


19.0 


52.0 


38.4 


42.7 


75-3 


White sweet clover: 












No inoculation 


2.5 


7.0 





2-3 


3-7 


Glue solution and soil 


11. 


11. 


35-6 


40.7 


74.0 


Sugar solution and soil 


10. 


18.0 


43-i 


46.0 


76.7 


Same weight of soil as seed . . . 


12.0 


42.0 


85-9 


91.0 


98.1 




39-0 


62.0 


9i-5 


98.0 


98.6 



hi the field trials with soybeans the larger amount of soil and the 
commercial culture appear to have given the higher percentage of 
inoculation at both locations on the first readings, and this difference 
held reasonably well thru the second reading made 74 days from sow- 
ing at University Farm and for the second and third readings made 
Y) and 04 flays from the date of sowing on the Coon Creek peat. 

The control seedings of both alfalfa and sweet clover show a some- 
what higher percentage of plants bearing nodules than the soybeans, 
but in every instance they could be easily recognized by comparison as 
( bance ii lorulat ions. Here, again, on the peat the same weight of. soil 
eed and the connnercial culture are superior to the other two 
methods of inoculation on the first reading, and this advantage is main- 
tained at each of the two later dates. 

At University Farm tlx- percentage inoculation for the plants where 
rune weight of soil as seed was used appears to have given no 

higher perr^ntage of inoculation on the first date than the other two 



ARNY & M'GINNIS ', INOCULATION OF LEGUMES. 297 

methods of using soil. However, there appears to have been a more 
rapid increase in the percentage at the second date than for the other 
two methods involving the use of soil. The commercial culture ap- 
pears to have given a higher percentage of inoculation here at both 
the first and second readings. 

In general at the time of the year the sowings were made there 
appears to be a more thoro inoculation of the plants in the peat than 
in the mineral soil. . 

The appearance of the plants with regard to thrift correlated rather 
closely with the results as given in the tables. The appearance of the 
plants where soil of the same weight as the seed was used and the 
plants inoculated by use of the commercial culture were generally 
larger and darker green in color than the plants which were from seed 
treated in the other two ways. The checks in most instances showed a 
definite lack of inoculation. 

Relation of Concentration of Solution to Soil Adhering to Seed. 

In the foregoing experiments only one strength of solution was used 
and the amount of soil adhering to the seed was not determined. 

In order to ascertain how much of the air-dry sifted soil adhered to 
the seed when sugar and glue solutions of various concentrations were 
used as compared with moistening the seed with water only, a number 
of pound lots of alfalfa and soybeans were weighed. These lots were 
moistened one at a -time with water and the various solutions of sugar 
and glue and weighed amounts of the soil applied. After a thoro 
mixing, suitable sieves were used to separate the soil from the seed 
with the soil particles adhering. With the soybeans there was no diffi- 
culty in making this separation, but with the alfalfa, on account of the 
small size of the seeds, the separation could not be made as sharply, 
and considerable unattached soil was left with the seed. The results 
given in Table 4 are the average for two trials in all instances except 
with the water, where only one trial was made. 

It is appreciated that the amounts of soil adhering may be influenced 
to a considerable extent by the degree to which the seed was moistened 
and the fineness of the soil. However, with conditions as uniform as 
possible for all lots, a tendency appears for the stronger solutions to 
cause additional soil to adhere to soybeans. With alfalfa the difficulty 
of separating the unattached soil from the seed with the soil particles 
attached probably masked any real effect of the different strengths of 
solutions. In no instance was the amount as low as a half pound or 
1 pound of soil per bushel of seed, which were the amounts used by 
Noyes and Cromer with unsatisfactory results. 



2C)8 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 4. — Comparison of the amounts of dry, finely sifted soil adhering to 
seed of soybeans and alfalfa seed moistened with water and solutions 
of sugar and glue of various strengths. 

Pounds ot dry soil adhering per 





60 pounds of seed. 


Material used in moistening seed. 


Soybeans. 


Alfalfa. 




4-3 


9-5 


Sugar. 5 percent solution 


4-5 


6.6 




5-3 


5.i 


Sugar, 20 percent solution 


6.7 • 


9.0 


Sugar, 30 percent solution 


8.8 


12.6 


Glue, 5 percent solution 


3-6 


7.2 


Glue, 10 percent solution 


3-0 


9.6 


Glue. 15 percent solution 


4-8 


8.5 


Glue, 30 percent solution 


5-6 


7-5 



Results of the Use of Solutions of Various Concentrations in Green- 
house and Field Trials. 

In order to ascertain the effectiveness of the inoculation when solu- 
tions of sugar and glue of various concentrations as compared with 
water only were used to cause soil to adhere to seeds, greenhouse and 
field sowings were made immediately after the seed had been treated 
unless otherwise indicated. The greenhouse trials were started Octo- 
ber 10, 1919, and read March 26, 1920. The field trials were sown in 
replicated rod rows on the Coon Creek peat and on adjacent light sandy 
soil May 6 and 7 and read July 7 and 8 and August 20, 1920, respec- 
tively. In the greenhouse trial the sandy soil was sterilized by steam 
before sowing the seed. The soybean plants on this soil were very 
abnormal in growth. The alfalfa was somewhat adversely affected by 
this soil treatment, but to a less extent than the soybeans. 

In the greenhouse trials with soybeans the inoculation was not satis- 
factory in the loam soil at the expiration of 166 days. The plants 
looked fairly thrift}', with some advantage in favor of the inoculated 
plants. ( to the sterilized sand 110 inoculation could be found on the 
plants which remained alive after [66 days. Sterilization of the soil 
and unsatisfactory growth probably accounts for the results. 'Fhe 
results reported for soybeans in Table 2 were secured from plants 
grown in the greenhouse during the summer. The growth of the 
plants and the inoculation were more satisfactory than that of those 
grown in the winter. ( )n the loam soil in the greenhouse all of the 
alfalfa grew (Veil and showed satisfactory inoculation at the end of 

the [66-da) period. On the sterilized sandy soil the growth of the 

alfalfa was less SatisfaCtOr) and there was a smaller number of nodules 
per plailf than on the loam soil. 

In these greenhouse trials, with the exception of the alfalfa on the 



ARNY & M GINNIS: INOCULATION OF LEGUMES. 299 

loam soil and the alfalfa treated with glue on the sterilized sandy soil, 
where there may be some correlation between the concentration of the 
solution used and the number of nodules per plant, there appears to be 
little justification for using the more concentrated solutions. 



Table 5. — Number of nodules per plant from various methods of inoculation. 





Greenhouse trial. 


Field trial. 


Crop and treatment. 


Loam, 


Sand, 


Peat. 


oand, 




166 days. 


166 days. 


62 days. 


106 days. 


62 days. 


Soybeans: 












No inoculation 

















Water and soil 


not included 


•4 


•4 


.1 


5% sugar solution and soil. . 


.1 





1.0 


1-3 


•4 - 


10% sugar solution and soil. . 


.8 





.1 


•3 


•9 


20% sugar solution and soil. . 


1.2 





1.3 


. .6 


1.4 


30% sugar solution and soil. . 


•5 





1.0 


i-7 


1.9 


5% glue solution and soil. . . 


1.0 





•4 


.8 


•7 


10% glue solution and soil. . . 


•5 





.8 


1.2 


.1 


15% glue solution and soil. . . 


•5 





.1 


1.6 


.2 


30% glue solution and soil. . . 


1.2 





.6 


•5 


1.4 


Equal weights soil and seed . . 


not included 


3-4 


2.6 


4.2 


Commercial culture 


do 


.1 


•3 


.1 


Alfalfa : 












No inoculation 





2.2 











Water and soil 


not included 


.6 


.6 





5% sugar solution and soil. . 


19.6 


15-8 


1.2 


.8 





10% sugar solution and soil. . 


28.7 


13.2 


•4 


•5 





20% sugar solution and soil. . 


33-9 


12.2 


2.0 


2.6 





30% sugar solution and soil. . 


39-0 


6.6 


i-5 


i-7 





5% glue solution and soil. . . 


24.7 


8.1 


1.1 


•7 





10% glue solution and soil. . . 


18.4 


8.1 


•5 


1.0 


.1 


15% glue solution and soil. . . 


29.2 


17-3 


•3 


•4 





30% glue solution and soil. . . 


39-i 


19.8 


•5 


• 7 





Equal weights soil and seed . . 


not included 


4.0 


5-6 


•5 


Commercial culture 


do 


6.9 


7-6 


4.0 



In the field trials with soybeans there was little difference in the 
number of nodules per plant on the peat and sandy soil at the end of 
62 days, when the first reading was made. An abundance of rain 
during this period provided ample moisture for growth even in the 
sandy soil. At the end of 106 days the number of nodules per plant 
on the peat was approximately the same as at the first reading. On 
the sand no readings could be made, due to the extreme drouth which 
had prevailed during practically the entire period between readings. 

Altho the number of nodules for the method where the same weight 
of soil as seed was used averages somewhat higher than that for the 
other soil method, there is not a significant difference if the figure 5.74 
is used as the measure. However, observations later in the season 
showed that this was the only satisfactory method of inoculation as 
indicated by the growth and thrift of the plants. 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



In this trial with the soybeans the commercial culture did not give 
satisfactory results. Other inoculations with material from the same 
lot of the commercial culture were made with negative results. 

On the peat soil inoculation of alfalfa, with the exception of the 
commercial culture and the method where a weight of soil equal to 
that of the seed was used, gave a low average number of nodules per 
plant at both the first and second readings. On the sandy soil, even 
with moisture conditions very favorable during the period up to the 
first reading, scarcely any indications of inoculation could be found 
except where soil to the same weight as seed and where the commercial 
culture were used. Later in the season the plants where these two 
methods had been used were observed to be dark green in color and 
of satisfactory growth as compared with the plants in the controls and 
where the other methods of inoculation had been employed. 

Effectiveness of Inoculation as Influenced by Delay in Sowing after the 
Inoculant has been Applied. 

On July 5, 1919, inoculation was applied to the seed of the soybeans 
and alfalfa. Five percent glue and sugar solutions were used to cause 
the soil to adhere to the seed. The commercial culture was applied in 
the usual way. Some of the dry soil was retained to use in applying 
the same weight of soil as seed at seeding time where that method was 
used. The seed was sown in white sand sterilized by steam and sup- 
plied with the necessary plant food, in sandy soil from Coon Creek 
sterilized by steam, and in a loam soil from University Farm. 

No sowings were made when the inoculant was first applied to the 
seed. On July 16 a sowing was made in the white sand. Sowings 
were made in the white sand as well as on the two soil types on Octo- 
ber 10. At the same time sowings were made of seed which had been 
inoculated on October 10 with glue and sugar solutions to cause the 
soil to adhere. The results are shown in Table 6. 

W ith the soybeans, particularly on the white sand, there appears to 
DC a falling off in the efficiency of inoculation due to storing the seed 
86 days after the firs! seeding. Taking into consideration results re- 
ported in other tables, storing the Seed 16 days did not lower the 
efficiency of inoculation to any appreciable extent. On the loam soil 
both fresh inoculation and inoculation applied [02 days previous to 
mowing gave rather unsatisfactory results. On the sterilized sandy 
~oil the restlltl were variable, largely due to the unsatisfactory growth 
Of soybeans on soil treated in tbis way. 

I 1 C retultl with alfalfa indicate that storing the seed 86 days follow- 



ARNY ft M'GINNIS: INOCULATION OF LEGUMES. 



301 



ing the first sowing on the white sand, at which time it had been stored 
16 days, did not lower the efficiency of the inoculant for plants grown 
in this material. On the loam soil there appears to have been no 
diminution of inoculating power due to storage of the seed 102 days 
after the inoculant was applied. On the sterilized sandy soil the re- 
sults with alfalfa were more uniform than with soybeans. The results 
from the seed stored after the inoculant was applied appear to be no 
lower than where the sowing was done immediately following this 
operation. 

Table 6. — Number of nodules per plant of soybeans and alfalfa when grown in 
greenhouse trials from seed stored after inoculation. 



Material in which the plants were grown, dates of 
inoculation, sowing, and reading. 





White sand. 


Loam soil. 


Sandy soil. 


Crop and method of 


Inocu- 


Inocu- 


Inocu- 




Inocu- 




lated 


lated 


lated 




lated 




inoculation. 


July 5. 


July 5. 


July 5. 


Inoculated 


July 5. 


Inoculated 




sown 


sown 


sown 


and sown 


sown 


and sown 




i July 


Oct. 


Oct. 


Oct. 10, 


Oct. 


Oct. 10, 




21, 


10, 


10, 


read 


10, 


read 




read 


read 


read 


March 26. 


read 


March 25. 




Sept. 


March 


March 




March 






25- 


28. 


28. 




25. 




Soybeans: 














Xo inoculation 




















5 percent sugar and soil .... 


5-0 


1.2 


.8 


.1 


3-5 







4.0 


1.0 


•9 


1.0 








Equal weights seed and soil . 


7-8 


1-7 


3-6 


not included 





not included 


A commercial culture 


16.7 


i-7 


3-1 


do. 


25 


do. 


Alfalfa : 








Xo inoculation 


•2 


2-5 


2.2 


3-5 


1.4 


2.2 


5 percent sugar and soil .... 


7.1 


5-6 


34-3 


19.6 


1.8 


15.8 




5-5 


5-5 


29.2 


24.7 


2.9 


8.1 


Equal weights seed and soil. 


9.1 


7-7 


20.6 


not included 


5-i 


not included 


A commercial culture 


i5-o 


16.2 


44-0 


do. 


4.9 


do. 



These results are similar to those secured by other experimenters. 
They appear to justify the conclusion that storing seed in a suitable 
place for a few days to a month or even for a longer period does not 
reduce seriously the effectiveness of the inoculant. 



Influence of Exposure of Inoculant to Sunlight. 
Finely sifted soil and a commercial inoculant were spread out thinly 
and exposed to October sunlight for a half hour and five hours. The 
soil was then applied to the seed, using a 5 percent sugar solution. In 
applying the commercial culture directions were followed. The seed 
was sown October 10 and the roots washed out and the results read 
March 28. These results are presented in Table 7. 



2,02 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Table 7. — Number of nodules per plant where inoculant was exposed to 

sunlight. 



Treatment. 


Soybeans. 


Alfalfa. 




. . . O.I 


19.6 


Soil exposed one-half hour 


. , . .1 


16.4 


Soil exposed five hours 


. . . .9 


10.7 


Commercial culture not exposed 


... 2.4 


29.O 


Commercial culture exposed one-half hour. 


... 2.7 


16.9 



The results with the soybeans were not satisfactory, being probably 
influenced by growing conditions in winter in the greenhouse. With 
the alfalfa, satisfactory inoculation was secured in each instance. 
However, exposure of soil for five hours and of the commercial culture 
for a half hour appears to have reduced materially the number of 
nodules per plant as read 167 days after the application. 

Sum mary. 

1. Five-percent solutions of glue and of sugar and the use of water 
only caused approximately 4.5 to 5 pounds of dry, sifted soil to adhere 
to a bushel of soybean seed. Twenty-percent solutions of these two 
materials caused somewhat more to adhere and 30-percent solutions 
caused the adherence of 5.6 to 8.8 pounds of soil to the bushel. 

2. For alfalfa seed the effect of the different concentrations of these 
solutions in causing soil to adhere to the seeds was probably masked 
by the inability to separate thoroly the loose soil particles from the 
seeds with the soil particles adhering. The amount of soil adhering 
per bushel of seed varied from 5.1 to 12.6 pounds. 

3. Inoculation varied with the crop, the soil, and growing conditions. 

4. On Sterilized sandy soil the growth and inoculation of soybeans 
in the greenhouse were not satisfactory. Alfalfa was affected less 
seriously. 

5. With a few exceptions, the plants where water only or glue and 
sugar solutions of various strengths were used with soil as the inocu- 
lant were found to have few, small, and scattering nodules, or none. 
The plants were uneven, many having the same appearance as the 
plant - in the controls. This method of inoculation is not recommended. 

6. The same amount of soil as seed, with one or two exceptions, 

• factory inoculation as indicated by the appearance of large 
nodules grouped about the Upper pari of the tap root, particulary in the 
ovl.can plants, and ri dark, green thrifty growth above ground. 

7. The Commercial culture, with the exception of one field trial and 
8 subsequent greenhouse trial of the same lot of the inoculant with 
soybeans, gave results similar and frequently more marked than from 
the 11 » of the same amount of soil as seed. 



arny & m'ginnis: inoculation of legumes. 



303 



8. With the exception of one trial with soybeans, storing the seed 
in a suitable place tor a short time after the inoculant was applied did 
not result in a serious lowering of the number of nodules per plant. 

9. Exposure of the soil to the sunlight of an October day for a half 
hour or for five hours and exposure of the commercial culture for a 
half hour did not alter the efficiency of these inoculants for soybeans. 
Exposure of the seed to the more intense heat of spring or summer 
sun might have produced different results. For alfalfa there appears 
to have been some reduction in efficiency where the soil was exposed 
for five hours and where the commercial culture was exposed a half 
hour. Apparently there was less injury by exposure than may usually 
be expected. It is recommended that exposure be avoided wherever 
possible. 

Literature Cited. 

1. Arny, A. C, and Thatcher, R. W. The effect of different methods of 

inoculation on the yield and protein content of alfalfa and sweet clover. 
In Jour. Amer. Soc. Agron.. 7: 172-185. 1915. 

2. Chester, F. D. The effect of desiccation on root tubercle bacteria. Del. 

Agr. Expt. Sta. Bui. 78, p. 1-16. 1907. 

3. Fellers. C. R. Report on the examination of commercial cultures of 

legume-infecting bacteria. In Soil Science, 6: 56-67. 1918. 

4. . The longevity of B. radicicola on legume seeds. In Soil Science, 

7: 217-232. 1919. 

5. Fred, E. B., axd Graul. E. J. The gain of nitrogen from growth of le- 

gumes on an acid soil. In Wis. Agr. Expt. Sta. Research Bui. 39, 
p. 1-42. 1916. 

6. Hopkins. C. G. Xitragin bacteria and legumes. 111. Agr. Expt. Sta. 

Bui. 94, p. 306-328. 1904. 

7. . Science and sense in the inoculation of legumes. 111. Agr. Expt. 

Sta. Circ. 86. p. 1-7. 2d ed. rev. April. 19 13. 

8. Magoox, C. A., and Daxa. B. F. Preparation and use of pure cultures for 

legume inoculation. Wash. Agr. Expt. Sta. Bui. 149. p. 1-16. 1918. 

9. Moore. George T. Soil inoculation for legumes. U. S. Dept. Agr., Bur. 

Plant Indus. Bui. 71, p. 1-72. 1905. 

10. Xobbe. F.. axd Richter. L. Uber den Einfluss des im Kulturboden vorhan- 

denen assimilierbaren Stickstoffs auf die Aktion der Knollchenbactieren. 
In Landw. Vers. Stat., 59: 167-174. 1903. 

11. Nobles. Charles. Spring inoculation of legumes. In Mich. Agr. Expt. 

Sta. Quarterly Bui.. 1 : 9I-U5- l 9*9- 

12. Xoyes, H. A., axd Cromer. C. O. Tests of commercial cultures for 

legume inoculation. In Soil Science, 6: 69-79. 1918. 

13. Temple. J. C. Studies of Bacillus radicicola. Ga. Agr. Expt. Sta. Bui. 

120, p. 67-80. 1916. 

14. Wilsox, J. K. Physiological studies of Bacillus radicicola of soybean 

and of factors influencing nodule formation. X. Y. Cornell Agr. Expt. 
Sta. Bui. 86, p. 367-4I3- I9i7- 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



A PLAN FOR THE CONDUCT OF FERTILIZER EXPERIMENTS. 1 

W. J. Spillman. 2 

It is a fundamental principle in experimental work that in order to 
learn the effect of a causal factor we must vary that factor while keep- 
ing all other causal factors constant. The results obtained from a 
series of fertilizer plats in which no account is taken of this principle 
can not, in general, be interpreted. A plat is of practically no value 
in a series unless it can be compared directly with others, and such 
comparison can not be made when two plats differ in more than one 
particular. Difference in the quantity of a mixture may be regarded 
as a single difference, altho it involves differences in more than one 
fertilizer element. In order to give results of the greatest value, a 
series of fertilizer experiments must also be planned so as to recognize 
the fact that the behavior of a fertilizer ingredient depends on the 
relative amounts of other fertilizer elements available to the growing 
crops. 

It is possible, with a relatively small number of plats, to obtain results 
that will not only be susceptible of definite interpretation, but will give 
reliable indications as to the results that would be obtained by the use 
of more or less of a given element than is actually used in the experi- 
ment. This phase of the subject will be discussed at some length in the 
latter part of this paper. 

In the accompanying tables will be found three different series of 
plats, each serving a different purpose in experimental work. Series I, 
the most complete of the three, is adapted to researcji work on the rela- 
tivc effed of different quantities of a fertilizer and of the various 
fertilizer elements in different combinations. This series involves 
< very possible relation between two, one, and no units of each of the 
three elements, nitrogen, phosphorus, and potassium. The results also 
include all the practical results of both the other series. Every plat 
in Series 1 is directly comparable with from six to fourteen other plats. 
In the case of each of the three elements nine 3-term comparisons are 
[>o ible. These arc given in the tables. In the case of each pair of 
element! three such comparisons an ' possible, and in the case of the 
three elements n^cr] together there is one 3-term comparison. These 
are all given in the tables. 

Series II is similar in purpose to Series I, but is designed for use 
in regions where it 1. already known thai one of the three elements is 
distinct^ more of B limiting factor than the other two. As outlined, 

! !<«•< re. e\ for publication I )<ccml>er 10, ]()jo. 

2 N "'!;«'' flit'.r >>i tin- lann Journal. Philadelphia, Pa. 



SriLLMAN : FERTILIZER EXPERIMENTS. 



305 



phosphorus is assumed to be this limiting factor. This series is de- 
rived from Series I by dropping out all those plats (except two men- 
tioned below) in which the amount of either nitrogen or potash is rela- 
tively greater than the amount of phosphorus. The plat receiving a 
unit of nitrogen (plat 2, Series II) and the one receiving a unit of 
potash (plat 10, Series II) are retained, since each of them increases 
by two the number of three-term comparisons that can be made in 
this series. 

To adapt Series II to a region in which some other element is the 
principal limiting factor, all that is necessary is to put the symbol of 
that element in the place occupied by the symbol P in the tables and 
put the symbol P in the place thus vacated. The smaller number of 
plats in this series should commend it to experimenters whose primary 
object is immediate practical results. Fewer comparisons are possible 
than in Series I, as shown in the outline of such comparison in the 
tables, but the number is sufficient to permit important conclusions. 

Series III is designed for the use of farmers who want to experiment 
on their own farms. Experimenters with limited funds might use this 
series to advantage. As outlined, it assumes that phosphorus is the 
principal limiting factor, and that potash is a more important ingredient 
of fertilizers than is nitrogen. Both these conditions hold in the long- 
time experiments at the Pennsylvania and Ohio stations and are prob- 
ably quite general in a large part of this country. The one comparison 
with potash is designed to show how much of this element may be 
profitably used along with phosphorus. The one comparison w T ith 
nitrogen is designed to show how much nitrogen may be profitably 
used along with phosphorus and potash. The phosphorus comparison 
is designed to give a line on the quantity of this element that can be 
used with profit. 

Series III may be adapted to a region in which the elements bear a 
different relation to each other by placing the symbol of the most im- 
portant element over the middle column, that of the next most impor- 
tant over the last column, and that of the least important over the first 
column in the outline of the series and of the comparisons to be made 
with the experimental results. 

The figure 1 occurring in the columns of the various tables signifies 
the use on the plat in question of such quantity of the element the 
symbol for which heads the column as will be equivalent to an annual 
application of the following quantities of fertilizer materials per acre : 

50 pounds of 16 percent nitrate of soda, . 
60 pounds of 16 percent acid phosphate, or 
40 pounds of 50 percent muriate of potash. 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



These are here designated as unit applications. The figure 2 signifies 
the use of twice these quantities. 

CHECK PLATS. 

In Series I each group of fertilized plats is preceded and followed 
by a check plat receiving no fertilizer. The first group consists of two 
plats (Nos. 2 and 3), the other groups of three plats each. In Series 
II there are fifteen fertilized plats, arranged in groups of three, each 
group being preceded and followed by a check plat. Only one check 
plat is inserted in Series III, as farmers will generally not take the 
trouble to use check plats after the manner of the experimenter. In 
the hands of a well-trained experimenter other check plats might well 
be inserted in this series, say, one following plat 7, and one between 
plats 3 and 4. 

Perhaps the best method of using check plats in determining the 
increase in yield due to fertilizers is that used at the Ohio station. It 
is as follows : 

The "check yield " of a plat is the yield that plat would presumably 
have made had it received the same treatment as the check plats. In 
what follows it is assumed that the plats, including check plats, are 
numbered consecutively. To find the check yield of a plat, subtract 
the number of the preceding check plat from the number of the plat 
in question ; divide the remainder by one more than the number of 
plats between the preceding and following check plats ; multiply the 
quotient by .the difference in yield of these two check plats; then add 
this product to the yield of the preceding check plat (subtract if the 
next check plat yields less than the preceding one). The final result 
is the "check yield " of the plat in question. 

To find the increase in yield dne to the fertilizer 011 a given plat, 
subtract it- ( heck yield from its actual yield. Increases arrived at in 

this manner are comparable for all the plats. 

CORRECTED YIELDS. 

It is often desirable to compare directly the yields of all the plats in 

1 ries 'not merely the increases dne to fertilizers). The yields may 
be reduced to a comparable basis as follows: Multiply the actual yield 
ca< li 1 fertilized ) plat by the average yield of all the check plats and 

divide the product by the check yield of the plat in question. The 

result ifl the " < orn < ted yield " of the plat. These corrected yields are 
comparable for all the plats. In them the variations in productive 
power ol the soil of the various plats are eliminated, in so far as this 

is jjossiblc. 



SPILLMAN : FERTILIZER EXPERIMENTS. 



307 



RELATIVE EFFECT OF SUCCESSIVE UNITS OF FERTILIZER. 

It is well known that a second unit of a given fertilizer does not 
produce as great an increase as the first unit, a third unit produces less 
increase than the second, and so on. German investigators, especially 
Mitscherlich, 3 have shown that there is much evidence to substantiate 
the assumption that the ratio between the increases due to any two 
consecutive units tends to be constant (that is, that the curve of in- 
crease is logarithmic). German writers refer to the law governing 
this rate of increase as the Law of the Minimum, tho the theory of 
the minimum factor really has nothing to do with the law. This phase 
of the subject is too complex to discuss in the space here available. 

The accompanying brief table illustrates the case in point. The 
second column shows the increases in yields of cotton at the various 
experimental farms of the North Carolina station, from the amounts 
of fertilizers in the first column. The third column shows the in- 
creases in yield calculated on the assumption that the ratio between 
successive increases is constant. W ith the exception of the second 
line the results agree very well with the experimental data. 



Fertilizer, lbs. 


Increase, Actual 


Bales, Calculated. 


Error. 


200 


0.205 


0.205 


0. 


400 


.400 


. -304 


.036 


600 


.480 


.488 


.008 


800 


.585 


.585 


0. 


1000 


.660 


.660 


0. 



Mitscherlich (I.e.) gives several other illustrations of this point. 

CALCULATING YIELDS. 

If C represent the constant ratio of successive increases in yield due 
to additional units of a fertilizer, and if I lf I 2 , 7 3 , etc., represent 
respectively the increases due to the first, second, third, etc., units, then 

I X = I X ; I = CI i; I, = CI, = C 2 I i; I 4 = CI, = C 3 I i; . . . 

I , = 0^1,. (0 

US represent the total increase due to n units of fertilizer, then, by 
adding the above equations together, we get 

$=I % + CI X + C*I X + . . . +C"- 1 7 1 =(i — C'OA/Ci — C). (2) 

In this equation n is the number of fertilizer units used. The equation 
3 Die Landwirtschaftlicken Versuchs-stationen, 1912, p. 413 et seq. 



308 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

applies for both whole and fractional values of n. When the increase 
for a single unit and the value of the ratio C are accurately known, 
equation 2 serves to calculate the increase to be expected from any 
quantity of the fertilizer in question, of course within the limits of 
normal increase due to fertilizer. 

To find the quantity of fertilizer giving the greatest profit, all that 
is necessary is to substitute for I n in equation I above the cost of a 
unit of fertilizer and to express I x in dollars and cents. The work is 
simpler when the equation is .transformed as follows: 

Taking the logarithm of both members, we have 

(n — i ) log C = log I n — log 7 lf 

from which 

11 = 1 + (log In— log A) /log C. (3) 

With accurate values for the various quantities used in equations 2 
and 3, the results obtained from such a series of experiments as Series 
I of this paper would enable us to determine the results to be expected 
from quantities of fertilizers other than those actually used in the 
experiments, as well as the maximum profitable quantity in any given 
case. 

Space will not permit me to show, what is actually the fact, that 
these simple equations, usable by anyone familiar with the use of 
logarithms, can easily be deduced from the much more complex and 
vastly more difficult equations of Mitscherlich, and vice versa. 

Series I of this paper gives nine values of C for each element, three 
values for each combination of two elements, and one value for the 
three elements used together. Series II gives three values for each 
dement, and Scries III one value. The average of the nine values 
from Series [, and even of the three values from Series II, should give 
a result usable in calculations. 



SPILLMAN I FERTILIZER EXPERIMENTS. 



309 



Series I, 



Fertilizers, 
applied. 



Plat Units 
No. NPK 



I 








* 


2 








1 


3 








2 


4 








" 


s 





1 





6 





1 


I 


7 





1 


2 


8 








r 


9 





2 





10 





2 


I 


11 





2 


2 


12 








► 


13 


1 








14 


1 





I 


15 


1 





2 


16 











17 


1 


1 





18 


1 


1 


I 


19 


1 


1 


2 


20 








O 


21 


1 


2 





22 


1 


2 


I 


23 


1 


2 


2 


24 











25 


2 








26 


2 





I 


27 


2 





2 


28 











29 


2 


1 





30 


2 


1 


I 


3i 


2 


1 


2 


32 











33 


2 


2 





34 


2 


2 


I 


35 


2 


2 


2 


36 












Direct comparisons possible in this series. 



Nitrogen. 


Phosphorus. 


Potash. 


N and P. 


Plat 


Units 


Plat 


Units 


Plat 


Units 


Plat 


Units 


No. 


NPK 


No. 


NPK 


No. 


NPK 


No. 


NPK 


1 











1 











1 











1 


000 


13 


1 








5 





1 





2 








1 


17 


1 1 


25 


2 








9 





2 





3 








2 


33 


220 


2 








1 


2 








1 


5 





1 





2 


001 


14 


1 





1 


6 





1 


1 


6 





1 


1 


18 


111 


26 


2 





1 


10 





2 


1 


7 





1 


2 


34 


221 


3 








2 


3 








2 


9 





2 





3 


002 


15 


1 





2 


7 





1 


2 


10 





2 


1 


19 


112 


27 


2 





2 


11 





2 


2 


11 





2 


2 


35 


222 


5 
17 



1 


1 
1 






13 
17 


1 
1 



1 






13 
14 


1 
1 







1 


N and K. 


29 


2 


1 





21 


1 


2 





15 


1 





2 






6 
18 



1 


1 
1 


1 
1 


14 
18 


1 
1 



1 


1 
1 


17 
18 


1 
1 


1 
1 



1 


1 
14 

27 


000 
1 1 
202 


30 


2 


1 


1 


22 


1 


2 


1 


19 


1 


1 


2 








7 





1 


2 


15 




1 





2 


21 


1 


2 





5 
18 


010 
111 


19 


1 


1 


2 


19 


1 


1 


2 


22 


1 


2 


1 


31 


212 


3i 


2 


1 


2 


23 


1 


2 


2 


23 


1 


2 


2 








9 
22 



1 


2 
2 






25 
29 


2 
2 



1 






25 
26 


2 
2 







1 


9 
22 

35 


020 
121 

222 




2 


2 





33 


2 


2 





27 
< 


2 





2 








10 





2 


1 


26 


2 





1 


29 


2 


1 





P and K. 


22 


1 


2 


1 


30 


2 


1 


1 


30 


2 


1 


1 










34 


2 


2 


1 


34 


2 


2 


1 


31 


2 


1 


2 


1 


000 


11 





2 


2 


27 


2 





2 


33 


2 


2 





6 


Oil 


23 


1 


2 


2 


31 


2 


1 


2 


34 


2 


2 


1 


11 


022 


35 


2 


2 


2 


35 




2 


2 


35 


2 


2 


2 


13 


100 










N, P and K. 










18 
23 


111 

122 










No. 


Units. 










25 


200 










1 
18 



1 



1 



1 










30 
35 


211 

222 










35 


2 


2 


2 















JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Series II. 



Direct comparisons possible in this series. 



applied. 


Nitrogen. 


Phosphorus. 


Potash. 


N and P. 


P and K. 


Plat 


Units 


Plat 


Units 


Plat 


Units 


Plat 


Units 


Plat 


Units 


Plat 


Units 


No. 


N P K 


No. 


NPK 


No. 


NPK 


No. 


NPK 


No. 


NPK 


No. 


NPK 




i 


o 





o 


i 


o 







I 





i 


o 








i 





i 





2 


o 


o 


I 


10 


I 





3 


I 


2 








I 


ii 


I I o 


4 


Oil 


3 





i 





3 





I 


6 


O 2 


3 





I 





18 


2 2 


8 


2 2 


4 


o 


i 


I 


1 1 


I 


I o 


2 


1 


4 





I 


I 


2 


1 


10 


10 


5 











4 





I I 


A 
1 


Oil 


6 





2 





12 


III 


12 


III 


6 


o 




() 


I 2 


I 


I I 


7 


O 2 I 


7 





2 


I 


19 


2 2 1 


16 


12 2 


7 
8 






2 
2 


I 

2 


6 





2 


10 


10 


8 





2 


2 








9 











14 


I 


2 I 


ii 


I I 


ii 


I 


I 





N and K. 


in , r ana iv. 


10 


I 








18 


2 


2 


14 


12 


12 


I 


I 


I 










1 1 


I 


I 





7 





2 I 


12 


III 


14 


I 


2 





3 


10 


i 





12 


I 


I 


I 


15 


I 


2 I 




12 1 


15 


I 


2 


I 


12 


III 


12 


III 


13 


o 








19 


2 


2 I 






16 


I 


2 


2 


6 


2 


20 


2 2 2 


14 


I 


2 


o 


8 





2 2 






18 


2 


2 





15 


12 1 






15 


I 


2 


I 


16 


I 


2 2 






19 


2 


2 


I 


20 


2 2 2 






10 


I 


2 


2 


20 


2 


2 2 






20 


2 


2 


2 










17 








O 




























18 


2 


2 


O 




























19 


2 


2 


I 




























20 


2 


2 


2 




























21 








O 





























Series III. 



Plat 



Fertilizers 
applied. 

Units 



Comparisons possible in this series. 



Nitrogen. 



No. 


N 


P 


K 


i 











2 


o 


I 


o 


3 


o 


2 





4 





2 


X 


5 


o 


2 


2 


6 


I 


2 


2 


7 


2 


2 


2 



Plat 

No. 



Units 
X P K 



Phosphorus. 



Plat 
No. 



Units 



Potash. 



Plat 



Units 



N 


P 


K 


No. 


N 


P 


K 








o 


3 





2 








I 





4 





2 


I 





2 


o 


5 





2 


2 



2 2 

1 2 2 

2 2 2 



THE INTERPRETATION OF WATER-REQUIREMENT DATA. 1 



R. S. Vaile. 2 

Some years ago the Utah Agricultural Experiment Station set forth 
the principle that the proper unit for measuring the crop-producing 
power of irrigation water is the crop produced per acre-inch of water 
rather than that produced per acre of land. Considerable data have 
been submitted by various Utah workers in which this unit is sup- 
posedly used in determining water requirements and duty of water. 3 
The present writer feels that many of these data have been presented 
with an emphasis that leads to erroneous, or at best only partially cor- 
rect, deductions and conclusions. Judging from the general form of 
the publications above referred to, they are designed primarily for the 
practical farmer and are expected to point the way to actual field 
practice. For this reason, particularly, the present writer feels that 
the data should be rearranged or the arrangement enlarged to include 
a factor that so far has been largely overlooked. 

The general statement that the acre-inch is the proper unit to use 
in measuring the crop-producing power of water is readily accepted, 
and its important bearing on farming operations should be urged on 
all irrigation farmers. In the determination of the yield per acre-inch 
of water applied, however, the starting point must be the expected dry- 
farm yield for the same crop on the same land. Only the increase in 
production above the usual unirrigated yield may be properly credited 
to the irrigation water. It is obvious that only in special cases will 
this point be zero. The Utah publications have used zero as a starting 
point in nearly all cases, or if they have considered the dry-farm value, 
it has not been given proper weight in their tables and conclusions. 
Fortunately, the published data give opportunity, in nearly every case, 
for a rearrangement on the basis of increase over dry-farm yields 
brought about by irrigation. 

The present writer desires to submit the following proposition : " In 
figuring the comparative crop-producing power of a definite amount 

1 Paper Xo. 73, University of California, Graduate School of Tropical Agri- 
culture and Citrus Experiment Station, Riverside, Cal. Received for publica- 
tion December 13, 1920. 

2 Assistant professor of orchard management. 

3 Note particularly Utah Agricultural Experiment Station Bulletin 115, 116, 
117, 118, 119. 146, and 157. 

3ii 



312 JOURNAL OF THE AMERICAN SOCIETY OF AGRON N MY. 

of irrigation water when used on various units of land, the same total 
area of land must always be considered and the dry-farm yield credited 
to any portion not irrigated by reason of increased application to other 
portions." In other words, if the, crop-producing power- of 30 acre- 
inches of water is being considered when all applied to 1 .acre as com- 
pared to an application of 5 acre-inches to each of 6 acres, then it is 
only fair in the former case to credit the total yield with the expected 
yield of 5 acres dry farmed. To illustrate, if 30 acre-inches of irriga- 
tion water are distributed 5 inches deep over 6 acres and result in a 
yield of 60 bushels per acre, the total result for irrigation, as expressed 
by the Utah writers, would be 360 bushels. If , on the other hand, the 
30 acre-inches were all used on one acre and the yield should be 150 
bushels for that 1 acre, then the Utah writers would form a comparison 
between 360 and 150 and conclude that it would be better irrigation 
economy to use the water distributed on all the land. Suppose, how- 
ever, that this same land is capable of producing 50 bushels per acre 
without irrigation, 5 acres would then produce 250 bushels. This 
added to the 150 bushels produced on the 1 acre irrigated with the 
30 acre-inches gives a total yield from the 6 acres of 400 bushels, or 
an increase of 40 bushels over the method of broader distribution of 
the water. This, the present writer believes, is the fairer basis of 
comparison. In applying the above method of comparing results to 
the data submitted in the Utah reports, several suggested conclusions 
are modified, at least in detail. The following typical examples are 
submitted : 

t. The crop-producing power of 30 acre-inches when applied to 
different areas of land cropped to corn is shown in Bulletin 117, Table 
10, to be 97.12 bushels when applied to 1 acre, 187.86 bushels when 
spread over 2 acres, 268.56 bushels on 3 acres, and 316.56 bushels on 
4 acres. 

Hill the dry-farm yield lias been forgotten! On page 85 it is stated 
1" be 13.7'' bushels per acre. Allowing for this yield on a sufficient 
area to complete the \ acres of land cropped in each case, the figures 
ju ' cited arc converted into the following: 

1 tU re irrigated, 3 acrei dry farmed, total yield, 228.40 bushels. 

2 acres Irrigated, 2 acres dry farmed, total yield, 275.40 bushels. 

3 acres irrigated, 1 acre dry farmed, total yield, 312.32 bushels. 

4 acres irrigated, total yield, 316.56 bushels. 

In thil raw the conclusion that the 30 acre-inches may most econom- 
ically he distributed over ,| acres is possibly still tenable, altho the 
margin of different j s vcr\ small and mi^ht not be sufficient to war- 



VAILE : WATER-REQUIREMENT DATA. 



313 



rant the extra expense involved in the irrigation of the larger area. 
The arrangement of the data as originally submitted, on the other hand, 
seemed to iifdicate an unquestioned superiority in favor of the distri- 
bution over the entire area. 

2. In Bulletin 116, Table 5, the following figures occur: 
Percentage of crop weight due to rain and soil water as compared 
to 7.5 acre-inches of irrigation water : Wheat, 86 percent ; corn, 80 per- 
cent; potatoes, 67 percent. Using these figures with the data pre- 
sented in Table 6 for the yield with J.$ acre-inches of irrigation, the 
following expected dry- farm yields of dry matter are obtained : Wheat, 
4,888 pounds; corn, 8,615 pounds; and potatoes, 1,829 pounds. 

If units of 50 acre-inches of water and 10 acres of land are used, 

Table i. — Results obtained from 50 acre-inches of irrigation water used in 
varying amounts on all or part of 10 acres of wheat, corn and potatoes, 
with the balance of the 10 acres dry farmed in each case. 

Wheat. 



Acres 
irri- 
gated. 


Acres 
dry 

farm- 
ed. 


Water 
per 
acre. 


Yield of dry- 
matter per acre. 


Total 
yield 
of 
dry 
matter. 


Yield of dry 
matter per 
acre-inch. 


Yield of dry 
matter per acre- 
inch as given 
in Table 6. 


Irri- 
gated. 


Dry 
farmed. 


Irri- 
gation 
water." 


Total 
water. 1 


Irri- 
gation 
water. 


Total 
water. 



10 

5 
2 
1 


10 

5 
8 
9 


Inches. 


5 
10 

25 
50 


Pounds. 


Pounds. 
4,888 
4,888 
4,888 

. 4,888 
4,888 


Pounds. 

48,880 

49,690 

52,860 

52,448 

5L99I 


Pounds. 


Pounds. 
355 
265 
282 
279 
277 


Pounds. 


Pounds. 

355 
265 
239 
172 

125 


4,969 
S.684 
6,672 
7-999 


994 
1,057 
1,049 
1.039 


994 
568 
267 
160 


Corn. 





» 



5 

10 
25 
50 




8,615 


86,150 




1,555 




1,555 








5 
2 
1 


5 
8 
9 


12,672 
14,606 
12,637 


8,615 
8,615 
8,615 


106,885 
98,132 
90,172 


2,137 
1,963 
1,803 


1,014 
93i 
854 


1,276 
584 
230 


821 
478 
209 



Potatoes. 








10 





10 







5 


5 




5 


10 


2- 


1/2 


7-1/2 


20 


1- 


1/9 


8-8/9 


45 



2,310 

2,925 
4,005 

3.795 



1,829 



18,290 

23,100 

1,829 23,760 
1,829 23,729 
1,829 20,475 



462 
475 
474 
409 



296 
207 
212 
212 
183 



462 

293 
200 

84 



a Based on the use of 50 acre-inches in all cases. 

6 Based on 50 acre-inches irrigation, plus ten times the rain and soil moisture 
as given for 1 acre (13.74 inches) in all cases. 



314 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



then the following tables may be compiled from the data submitted 
above and those found in Table 6 (Utah Bulletin 116). The choice 
of these particular units is, of course, entirely arbitrary, except that 
the proportion between acre-inches and acres of land is such that the 
entire tract will just be covered by the smallest irrigation application 
used in the experiments. 

The striking thing brought out by the above figures is the difference 
in ratio between the amounts of dry matter produced by a given amount 
of irrigation water when used in various ways, as determined by the 
two methods of comparison. This difference depends upon whether 
the unit of land used for the total yield is kept constant by including 
the dry-farm yield on the unirrigated portions, or whether the unit of 
land cropped is changed to correspond only to the amount covered 
with irrigation water. It seems to the present writer that the latter 
method (which is the one used by the Utah authors) is open to criti- 
cism in that it introduces so obvious a variable in the extent and value 
of the original plant as well as in the labor outlay. It is even further 
at fault in that it does not give sufficient weight to the rain and soil 
moisture, for in the case of the distribution of the irrigation water over 
the 10 acres the amount of water furnished by nature is not limited to 
13.74 acre-inches (the figure used in case of wheat), but becomes ten 
times that amount. 

3. In Bulletin 146 of the Utah station the following statement oc- 
curs: " The total yield (produced by natural soil moisture and 20 inches 
of irrigation water) was more than three times as much when the 20 
acre-inches were used on 4 acres as where the water was all applied 
to 1 acre"(p. 25). The obvious implication would seem to be that it 
were decidedly better irrigation economy to spread the 20 acre-inches 
river the j acres. However, in case all the water is used on I acre, 
the other 3 acres are forgotten in arriving at this conclusion, altho the 
complete data of yields as listed on page 30 show a considerable dry- 
farm possibility for them. I'tilizing the data presented on page 30, 
Table j has been compiled. 

From Table 2 it becomes evidenl that the distribution of the 20 

.'i' re ni< hc> over the j ai res is very little better than the use of the 
entire amount on 1 acre, with the other 3 acres dry farmed. In fact, 

the difference indicated is not greater than the experimental error that 

' I to be expected in SUCh field trials. In this case, the conclusion stated 
b) 'be authors of the bulletin, namely, that the best practice seems to 
be to irrigate with 15 acre inches divided into three applications, still 
hol<K. In tin- 1 c t example the soundness of the authors' deductions 

r|o< not eem so < lear. 



VAILE : WATER-REQUIREMENT DATA. 



315 



Table 2. — Yields of wheat obtained from 20 acre-inches of irrigation water 
used in varying amounts on all or part of 4 acres, with the 
balance of the 4 acres dry farmed. 



Acres. 


Water 
used per 
acre. 


Xo of 
applica- 
tions. 


Yield 


per acre. 


Total 
yield on 
4 acres. 


Irrigated. 


Dry farmed. 


Irrigated. 


Dry farmed. 






Inches. 




Bushels. 


Bushels. 


Bushels. 





4 









37-3 


149.2 


*i 


2! 


15 


3 


52.4 


37-3 


199.4 


2 


2 


10 


2 


45-i 


37-3 


164.8 


4 





5 


1 


40.8 




163.2 


1 


3 


20 


4 


45-7 


37-3 


157-6 



4. In the summary of Bulletin 157, item 4 states "one inch weekly, 
or a total of T2.8 inches during the season, gave a higher yield than 
any other treatment." The author has evidently forgotten for the 
moment his oft-repeated slogan that the unit of measure for irrigation 
economy should be the acre-inch of water rather than the acre of land. 
For the purpose of compiling a comparative table from the data sub- 
mitted in the above bulletin, the present writer has taken the arbitrary 
units of 45 acre-inches of irrigation water to be used on all or any 
part of 9 acres of land planted to potatoes. (The reason for using this 
proportion between land and water is again found in the fact that it just 
accommodates the smallest quantity of water used in the experiments, 
when distributed over the entire area.) The data in Table 3 result. 



Table 3. — Yields of potatoes obtained from 45 acre-inches of irrigation water 
used in varying amounts on all or part of 9 acres. 



Number of acres. 


Total 
water used 
per acre. 


Stage 
at which 
applied. 


Yield per acre. 


Total 
yield on 
9 acres. 


Irrigated. 


Dry farmed. 


Irrigated. 


Dry farmed. 






Inches. 




Bushels. 


Bushels. 


Bushels. 





9 









153-3 


1.379-7 


9 





5-o 


3- 


229.0 




2,061.0 


3-5 


5-5 


12.8 


1 inch 


337-1 


153-3 


2,032.0 








weekly 








4-5 


4-5 


10. 


3. 4- 


255-4 


153-3 


1,838.1 


2.25 


6-75 


20.0 


1. 2, 3, 4. 


317-3 


153-3 


1,748.6 


3 


6 


15.0 


1. 3. 4- 


257.2 


153-3 


1,691.4 



The present writer does not have in mind a complete discussion of 
the economics of irrigation agriculture in this paper ; there are certain 
definite principles and many variable factors that can not even be 
mentioned. It is generally held that the margin of financial profit in- 
creases with the increase in yield per acre, only up to some fixed point ; 



316 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



it is commonly recognized that dry- farm crops have a greater value 
than the same weight or bulk of irrigated crops, because of superior 
quality; there is a varying labor cost in the application of irrigation 
water, dependent in part upon whether a given amount of water is 
distributed over a limited or extended area; in certain cases the dry- 
farm yield can not be produced at a financially profitable figure ; all 
these and many other considerations must be in the farmer's mind 
before he determines just what system will give the greatest economy 
in water usage on his particular farm. The present writer feels, how- 
ever, that the method of figuring water duty suggested above has much 
to commend it to the practical operator and is less likely to be mis- 
leading than the method used in the publications reviewed. 

All of the above tabulations or illustrations are designed to show the 
reasonableness of the proposition stated at the beginning. For sake 
of clearness, let us restate it in conclusion : " Given a farm of definite 
area and a definite amount of available irrigation water ; given, further, 
the possibility of producing profitable crops under a system of dry 
farming ; then, in case the irrigated area is decreased by increasing the 
acre application of a part of the farm, it is not fair to assume that the 
total area cropped will be reduced, but rather that the land released 
from irrigation will still maintain its dry-farming value. " There is 
nothing in this proposition that in any way interferes with the principle 
that the acre-inch of water should be used as a unit in measuring 
water economy, but it merely suggests a method of utilizing that unit 
fairly. 

COMMENT ON R. S. VAILE'S DISCUSSION OF UTAH RESULTS. 

i 

F. S. Harris. 1 

In bis discussion of irrigation experiments at Utah, Professor Vaile 
1 mu< h emphasis Ot) the need of giving proper consideration to the 
- top producing power of the natural precipitation independent of the 
irrigation water applied. He shows a method of arranging the irri- 
gation data in a way that will help the user of water to decide how 
Dmcfa to apply as a Supplement tO dry fanning. His method of ar- 
ranging the material is interesting just as any additional way of pre- 
senting fads brings onl interesting relations. Many such ways of 
arranging our material have presented themselves to lis, but have not 

1 Formerly director, Utah Af<ricultural Experimental Station, Logan, Utah. 



HARRIS I DISCUSSION OF UTAH RESULTS. 



317 



been used because of their limited application and because we felt that 
those who wished could work out these relationships from the data. 

I am sorry that Professor Vaile should be misled concerning the 
irrigation philosophy of either Dr. Widtsoe or myself, as his paper 
indicates that he is. For example, in discussing Utah Station Bulletin 
147, he says that "the obvious implication would seem to be that it 
were decidedly better irrigation economy to spread 20 acre-inches over 
4 acres." I fail to see how he reached this conclusion when the sum- 
mary of the work states clearly that " these experiments show rather 
conclusively that on the deep soils of Utah the best system of irrigating 
wheat is to apply three irrigations of about 5 inches each." 

Of course, the efficiency of- each inch of water is greater with the 
lower applications of water, but other factors, such as labor, cost of 
land, and many other items, must be taken into consideration in decid- 
ing on the practice that is best to follow. There is nothing sacred 
about either the water or the land except as they contribute to the 
welfare of man ; hence the efficiency of either the acre-inch of water 
or the acre of land is not the ultimate end to be sought. The real aim 
should be to use the land and water together in such a way that man 
will be best served. Where water is the chief limiting factor, it should 
be given first consideration; where land is scarce, its efficiency needs 
special attention. 

We have used as a basis of all our irrigation studies the idea that 
irrigation water should be used as supplementary to the natural pre- 
cipitation, or as Dr. Widtsoe has stated it, " The beginning of irriga- 
tion wisdom is the conservation of the natural precipitation." In most 
of our publications we have stated as nearly as we could what per- 
centage of the crop came from the precipitation and what from the 
irrigation. 

Probably the chief limitation in Professor Vaile's method of compu- 
tation comes from the fact that in most places where irrigation is prac- 
ticed no profitable crop can be raised at all with the rainfall unless it 
is supplemented by irrigation water ; hence it is impossible to consider 
any dry-farm crop on the unirrigated acres and no accurate calculations 
can be made with this as a basis. This is the main reason why we 
have not made this computation, even tho on our Greenville farm 
there is sufficient rainfall to mature dry-farm crops. Over much of 
the State economical crops can not be produced without irrigation. 



VARIETAL NOMENCLATURE OF OATS AND WHEAT. 1 



George Stewart. 2 

Varietal nomenclature of the small cereals is far from satisfactory. 
This is due in part to the fact that commercial varieties have been 
introduced with the same names that were used to designate them 
while they were still on test at some experimental farm. This is good 
practice when the names are desirable, but such is not always the case. 
Importations from foreign countries have occasionally brought their 
native names with them. Some of these names are long and have no 
particular suggestiveness in America, tho they may have had in France, 
Russia, Algeria, or Turkestan. Many foreign words are difficult for 
English-speaking people to pronounce and are more than ordinarily 
hard to spell. At home, names of imaginary or extravagant qualities 
have at times been added for one reason or another. Finally, the name 
of s< une man or experiment station, whether worthily or unworthily 
does not matter, has become attached to several varieties of widely 
different qualities or adaptation. When a number is made part of such 
a name the trouble is increased. 

Two pieces of work have greatly improved conditions with respect 
to classification, or at least opened the way for such improvement. Dr. 
W. C. Etheridge, 3 now of the Missouri station, while a graduate stu- 
dent at Cornell University made a careful study of oat varieties. He 
worked with a collection of about 600 varieties that Prof. E. (i. Mont- 
gomery had gathered in America and Europe. Less than 60 of these 
W€Tt found to be actual botanic varieties, the others all being duplicates 
of One or another of the accepted forms. A wheat varietal study of 
even larger proportion is now being conducted by Clark, Martin, and 
Hall. 1 of the ( M'liec of (Vreal Investigations, United States Department 
of Agriculture. 

liotli of these studies are classic in the fields they represent, the 
classification of varieties of oats and wheat. Suitable names are of 

1 Contribution from the Department of Kicld Crops, Utah Agricultural Kx- 
' • ' Million. I. ..-.in, t't;ili. Received for publication October 20, 1920. 
I'lote .,, ,,f agronomy, Utah Agricultural College. 

■Etheridge, W. C. A classification of the varieties of cultivated oats. N. Y. 

Cornell Art. Kxpt. St a. Memoir 10, 1916. 

♦Clark. J. A.. Martin. J. II., and Hall, C. R. Preliminary classification of 
Ann ri eat varieties. In manuscript. 

3ifl 



STEWART: NOMENCLATURE OF OATS AND WHEAT. 



319 



secondary, tho not of negligible, importance. From this standpoint 
neither piece of work is all that could be desired, in spite of the fact 
that each has appreciably improved the varietal nomenclature of the 
crop studied. It would be too much to expect such large fields to be 
cleared in one stroke. 

Etheridge chose the name for his variety by a sort of ballot system — 
that is, he kept count of the number of times a given variety was 
observed to bear a given name and gave to the variety the name applied 
to it the greatest number of times. Probably a more impartial method 
could not have been found, but it gave a troublesome or an unwieldy 
name an equal opportunity with a desirable one. 

In the wheat classification study an effort is being made to get back 
to the original, or rather to the rightful, name of a variety from the 
standpoint of historic justice. This method seems to have more to 
recommend it than does the method used for oats. It should be 
emphasized that both methods are superior to the one to be herein sug- 
gested, if there is anything peculiarly sacred about a name in and of 
itself. 

In this article any such intrinsic value is ignored when the original 
name is particularly objectionable for some reason. In other words, 
the author contends that unwieldy, troublesome, or extravagant varietal 
names should be replaced by simple ones, if at all in keeping with the 
popularity or historic justice of any given name. Frequently the orig- 
inal name can be modified in such a manner as to make it simple and 
safe. At any rate, new varieties should not be encumbered needlessly. 

Numbers are necessary in experimental work to designate strains, 
but not for commercial varieties, where they offer chances for error. 
The fact that one variety of wheat is known in Xew York as Forty- 
fold, Xo. 6, International Xo. 6, Rochester No. 6. Genesee Xo. 6, 
Michigan Xo. 6, Clawson No. 6, Jones Xo. 6, and Xo. 16 shows the 
meaninglessness of numbers. There is no way of telling from the 
name alone that Jones Xo. 6 is an absolute synonym of Genesee Xo. 6 
or of Fortyfold. The names Xo. 6 and Xo. 16 would be accepted as 
the names of separate varieties. The name part of the varietal desig- 
nation is much more significant than the figures and leads a person to 
believe different varieties are indicated by the names Clawson Xo. 6 
and Jones Xo. 6, for example. Should some seedsman drop off the 
number, the confusion would then be complete. The use of numbers 
of any kind for trade names affords opportunity for entanglement, and 
hence for error. The author, therefore, favors the abandonment of 
all numbers from the nomenclature of commercial varieties. 



320 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Troublesome as numbers ordinarily are, they have infinitely more 
possibilities for mischief when they are so similar that a slip of the 
pencil or of the typewriter would change one into the other. Espe- 
cially unfortunate in this respect are two varietal names of oats, Garton 
No. 748 and Garton No. 784. The only difference in the names is the 
interchange of the 8 and the 4. Warburton holds the opinion that this 
is the way in which No. 748 came into existence, No. 784 having been 
the original designation. In 191 7 the author reported some work on 
classification of oat varieties that he had done at Cornell University. 
In one of the paragraphs the " 748 " was written " 784." This later 
caused him much trouble. Garton No. 473 and Garton No. 691 are 
possibly less dangerous, for none of the figures are identical ; but should 
a typist leave off either of the numbers trouble would follow, as the 
term "Garton" could not serve to identify the variety if it is used as 
part of more than one varietal name. 

The C. I. numbers of the oat key further illustrate the danger of 
numbers. They are as follows : C. I. No. 602, C. I. No. 620, C. I. No. 
603, and C. I. No. 606. A glance shows how easily 620 and 602, 
602 and 603, or 603 and 606 could be mixed, and consequently 
muddled. 

Besides the numbers'used as names, several others are fraught with 
possibility of error. " Silvermine " and " Silvermine Selection " are 
used for two distinct varieties. The word " Selection 99 is attached to 
several other names. Such combinations of names as Victor and Irish 
Victor, Golden Giant and Golden Drop, Green Russian and Green 
Mountain, Storm King, Tartar King, and White Tartar deserve con- 
sideration. Compare with them a few of the simpler names, such as 
Lincoln, Belyak, Silvermine, Joannette, Culberson, and Burt. Simple 
one-word names are especially distinctive. Double names, such as 
Swedish Select, Red Rustproof, Danish Island, and Green Mountain, 
arc probably satisfactory, but have no advantage over the single-word 
names. Because the words Tobolsk and Probsteier do not end in 
English syllables both are difficult to pronounce and hard to spell. 
Tho Strange, Belyak and Mesdag are easy to spell, because the syllables 
are in pronoun< cable English. None of the last four names, however, 
is suggestive in English. 

Finally, " ( iarton " is repealed several limes in widely separated parts 
of the key, usually with a number added. Let a typographical error 
OCCtir in which the number is losl or mixed, and identity has disap- 
; fared < ompletely. 

The Washington Agricultural Experiment Station has continued 



STEWART : NOMENCLATURE OF OATS AND WHEAT. 



3^1 



many of its pedigree, or line, numbers as varietal names of wheat when 
later introduced commercially. Some of these are : Washington 3, 
"Washington 60, Washington Hybrid 63. Washington Hybrid 123, 
Washington Hybrid 128, and Washington Hybrid 143. All the objec- 
tions to numbers mentioned in the discussion of varietal names for 
oats apply here. Numbers such as 3 and 63, 123 and 128, 123 and 
143, or 60 and 63 are combinations that render confusion easy, even 
by the slightest typographical error. Since the word " Washington " 
is attached to six distinct varieties, this part of the name the part that 
should be distinctive, means next to nothing. In two of the names the 
number is added directly to the word " Washington." whereas in four 
others the word " hybrid " intervenes. This complicates matters by 
making the names sb long as to be unwieldy. 

Some other numbers that look as if they could easily cause trouble 
are Rural Xew Yorker Xo. 6 and Rural Xew Yorker Xo. 57. Ne- 
braska Hybrid 28 might easily be confused with Washington Hybrid 
128. The number part of Buftum X'o. 17 adds nothing to the signifi- 
cance of the name, since " BurTum " appears just this once in the entire 
key of wheat varieties. There also seems to be no necessity- for two 
names like Jones Longberry Xo. 1 and Silversheaf Longberry. One 
might just as well be merely Longberry and the other Silversheaf. 
Xote the cumbersome length of Tones Longberry Xo. 1 and Rural 
Xew Yorker X'o. 57 when compared with shorter names such as Mar- 
quis, Prelude, Humpback, Gypsy, and a number of others. 

In addition, there are some outright invitations for entanglement in 
the names themselves. Take, for example. " Ruby " and u Rudy." 
In this pair the exchange of a " b M and a " d " causes a complete change 
of variety, correctly spelled and to all appearances a correct name. 
"Humpback" and "Humpback II" otter similar facilities for loss of 
identity-. In some cases repetition of part of the name is frequent, as 
in Martin Amber. Mammoth Amber, and Imperial Amber. The same 
is true of White Fife. White Track, and White Winter. In addition, 
the last two names might be equally significant when applied to a num- 
ber of other varieties. 

A few oddities have also survived in the key, such as Kota. Xorka. 
and Oatka. Somehow these have missed accomplishing what Kanred 
and Dicklow do so admirably. Then K. B. Xo. 2 and D 5 are pecu- 
liarly ineffective as names. Here the dangers from numbers and from 
non-suggestive names are combined. 

The Canadian names, Marquis and Prelude, show up well as ex- 
amples of simple names when compared to Washington Hybrid 128, 



322 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Fultzo-Mediterranean, or even Dawson Golden Chaff, to say nothing 
of Silversheaf Longberry or Extra Early Windsor. 

Some more names too long or too awkward to be satisfactory are 
Regenerated Defiance, Diehl-Mediterranean, Jones Winter Fife, Eng- 
lish Squarehead, and Squarehead Master. The same is true, only in a 
somewhat lesser degree, of such names as Colorado Special, California 
Gem. Wyandotte Red, Early Red Clawson, and Sommerweizen. Com- 
pare these for brevity with Bobs, Dicklow, Turkey, Kanred, Fultz, 
Huston, Poole, Glyndon, Wellman, Ruby, Kofod, Sevier, Indian, 
Sonora, Gypsy, and a host of others. The shorter names are more 
effective and lack the constant nightmare of misspelling that is almost 
sure to haunt the path of such names as Marouani, Sommerweizen, 
Diehl-Mediterranean, and even of Coppei and Washaho. 

Conclusions. 

All numbers when used as part of the name of a commercial variety 
are bunglesome; some combinations are dangerous so far as accuracy 
is concerned, since only the slightest slip of pen or typewriter is neces- 
sary to cause a complete loss of identity. It seems the better part of 
wisdom, therefore, to discard any numbers from the name of a com- 
mercial variety, notwithstanding the indispensability of numbers for 
experimental work. 

Where possible, long names should be avoided either by using one 
part of the name or by compounding a part of one of the name words 
with a part of the other, as in Kanred, Minhardi, and Dicklow. Care 
is. of course, necessary, or ridiculous names may result. In a few 
cases 11 might be better completely to discard a long name, at least a 
much-compounded one, and to re-christen the variety with a short one- 
word name. 

SUGGESTIONS. 

Montgomery 8 has suggested that a registry book be started for crop 
varieties. In this book would be recorded a description, a statement of 
the adaptation, and as much history of a variety as is available. When 
a new introduction is to be made, its description and history would be 
!(■< nrded. Specimen types might also be kept in a herbarium of some 
' later workers to identify with certainty the varieties with 
wln< li they are working. After a few years such a book and her- 
barium would begin to acquire historic as well as practical value. 
This work would most likely be assigned to the State or National 
department of agriculture. 

■ " • i '.. On naming varieties. /// J<>ur. Auht. Soc. Agron., v. 

7. P. *>-3>. 1915. 



BROWN : TEACHING SOIL BACTERIOLOGY. 



323 



An organization such as that which manages the Jersey or Holstein 
herd-books might be advisable. The adoption, and coinage if deemed 
best, of new names might be left to some officer or committee in the 
organization. Names are not scarce. Some simple ones already used 
for oats are President, Wideawake, Prosperity, Abundance, National, 
Sensation, Welcome, and Roosevelt. For wheat a list of simple names 
has already been given. At any rate, the experimental number would 
not be part of the commercial name. 

THE TEACHING OF SOIL BACTERIOLOGY. 1 

Percy Edgar Brown. 2 

Soil bacteriology as a science is of comparatively recent development. 
Its newness is evidenced by the way in which the subject is taught, but 
more particularly by the fact that it is not included at all as a separate 
course in many of our agricultural college curricula. 

With the accumulation of information regarding the bacteriology of 
the soil, however, resulting from the extensive investigations along 
this line in recent years, the importance of the subject is becoming 
more and more widely recognized and most institutions are now 
awakening to a realization of the fact that the study of soils is almost 
as incomplete without bacteriology as it would be without chemistry. 
Indeed, it is quite generally conceded that three factors, the chemical, 
the physical, and the bacteriological, control the fertility or crop-pro- 
ducing power of soils, and that these factors are of about equal 
significance. 

The teaching of soil bacteriology is therefore a subject of much 
interest and importance at the present time. The purpose of this paper 
is to call attention to the need for special courses in this science and 
to discuss the place which such courses should occupy in the curriculum 
and the ways in which the subject matter may be presented. 

Soil bacteriology is an applied science, an application of bacteriology 
to soil science, and thus to agricultural science. Hence the teaching of 
the subject will be considered only in connection with agricultural 
courses. General bacteriological courses should undoubtedly include 
some reference to the relation of bacteria to soils, but obviously mere 

1 Paper presented at the meeting of the Society of American Bacteriologists 
held in Chicago. 111., on December 29. 1920. Contribution from Iowa State 
College. Ames, Iowa. Received for publication January 10. 1921. 

2 Professor of soil bacteriology, Iowa State College. 



324 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



fundamentals can be presented in this way. Such a bird's-eye view, 
as it were, of the subject is probably sufficient for general science 
students. In agricultural courses a more comprehensive study of the 
part which bacteria play in maintaining soil fertility is quite necessary 
if the student is to acquire a proper viewpoint of farming practices 
and any adequate conception of the essentials of successful crop 
production. 

Soil bacteriology has a place, therefore, in the curriculum of every 
agricultural college in connection with other soils courses. Further- 
more, it is of so much importance that it should be given as a separate 
course and not, as is so often the case, considered only in a brief way 
in connection with a general course in soils or in soil fertility. 

It has been well said that the whole business of agriculture is founded 
upon the soil, and the presentation of the science of soils in more than 
one course is now more than a matter of expediency. It is absolutely 
necessary if the student is to secure a thoro understanding of the sub- 
ject. It is not in place to consider here what these various soils courses 
should be called, nor what they should include, except in so far as they 
affect the teaching of soil bacteriology. Suffice it to say that experi- 
ence along this line at the Iowa State College indicates that a general 
course in soils should be followed by a course in soil fertility, this in 
turn by soil bacteriology, and the final course, involving a practical 
application of the other three, should be soil management. This ar- 
rangement of courses shows quite clearly the importance attached to 
-nil bacteriology, and it also indicates the desirable prerequisite soil 
courses. According to this plan soil fertility is a prerequisite for soil 
bacteriology and soil fertility requires the completion of the general 
course ill soils, hence both these courses must precede soil bacteriology. 
I'ut oilier general science courses are also necessary and the student is 
required to complete a course in general bacteriology and two years' 
work in chemistry before taking up soil bacteriology. In fact, the 
chemical courses are prerequisites to soil fertility. Thus upon the 
foundation of chemistry, bacteriology, and soils there is erected the 
superstructure of soil fertility, soil bacteriology, and finally soil man- 
agement. With the omission of any one of these parts, the structure 
would he incomplete. With soil bacteriology left out, soil manage- 
ment would become a collection of unconiprehenclecl data, of uncorre- 

lated facts, and of unexplained recommendations. In short, soil bac- 
teriology is the key which provides the solution of many of the 

U ■ < of Crop growth in relation to soil conditions, those mysteries 

which have for centuries puzzled the fanner and evaded explanation 

by the scientist. 



BROWN : TEACHING SOIL BACTERIOLOGY. 



325 



The importance of teaching soil bacteriology in connection with other 
soils courses seems quite evident and the prerequisites which the course 
should carry should undoubtedly include chemistry, bacteriology, and 
soils. The next question which arises pertains to the method by which 
the subject should be taught. 

In all teaching there seems to be a wide diversity of ideas regarding 
the proper methods to be followed. Some pedagogical experts present 
lengthy arguments in favor of certain methods of procedure, while 
others have quite as extensive support for an entirely opposite posi- 
tion. It is probably true that teaching methods, at least of science 
subjects, should be adapted to the particular science, and it seems 
rather unreasonable to expect the same methods to prove adapted to 
the wide variety of science subjects which are now included in our 
college and university curricula. 

With all due respect to our good friends, the pedagogs, it appears 
that specialists in particular branches of science are really much better 
qualified to select the best method of presenting their subjects to college 
students than are educational experts who may have no clear concep- 
tion of the subject matter to be presented, and certainly can not have 
any extensive insight into a wide range of science subjects, such as 
would be necessary if they were to adapt their teaching ideas to various 
sciences. 

In new sciences it is particularly difficult to determine the method 
of teaching and what should be taught. In older sciences there are 
many textbooks and laboratory guides embodying the results of the 
teaching experience of many specialists. From among the various 
methods suggested each teacher may choose that particular one which 
seems more nearly to be adapted to his conditions and most closely to 
meet his requirements. 

In soil bacteriology there are no textbooks which are adapted to 
special courses in the subject. It is true that many bacteriologies con- 
tain excellent sections on the subject and a few soil texts consider at 
some length the relation of bacteria to soil fertility. In no case, how- 
ever, is the material presented with sufficient completeness or prepared 
in a satisfactory way to meet the requirements of a separate course in 
soil bacteriology. Some day many texts on the subject will undoubt- 
edly be available, but it is probably just as well that this is not true 
now, for many of our ideas along soil bacteriological lines are under- 
going considerable change and the newer phases of the subject are 
developing very rapidly and are beginning to demand more attention. 
Rearrangements and many readjustments are therefore constantly re- 



326 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



quired in subject-matter outlines. Hence the time seems hardly ripe 
for textbooks on soil bacteriology. 

In the absence of textbooks, the lecture method must be followed 
or a modified lecture method consisting of a combination of lectures, 
specially prepared notes, and quizzes. Inasmuch as soil bacteriology 
is a rather advanced course and can not come early in the college 
course, the lecture method seems entirely satisfactory. Ten years' 
experience with this method at Ames has confirmed this conclusion. 
Furthermore, it has been found also that the subject proves very attrac- 
tive to students, and no difficulty has been experienced in securing and 
holding their interest without textbooks or outlines. In fact, it seems 
that the lack of these usual accompaniments of a study brings about 
more attention and a greater effort to acquire a full understanding of 
the subject. Outlines have a tendency to reduce the interest of the 
student and to cause him to slight the taking of notes, questioning their 
value. The same result comes from providing full notes on the lec- 
tures, and to an even greater extent. Oral and written quizzes are, 
of course, quite desirable in connection with the lecture work, particu- 
larly the former, as opportunity is thus afforded for correcting any 
misconceptions which may have arisen in the students' minds, and for 
emphasizing important points, as well as for determining to what ex- 
tent the students have grasped the subject. 

In general science as well as in applied science courses it has been 
commonly conceded that laboratory instruction in connection with class- 
room work is very desirable, if not absolutely necessary. There seems 
no reason to question tin's conclusion when soil bacteriology is consid- 
ered. It is. of course, quite possible to teach the subject without 
laboratory work, just as in the case of other sciences, but "seeing is 
believing/' and the student who really studies the bacteria and their 
action in the laboratory most certainly receives and retains far more 
information on the subject. It becomes more of a reality to him, more 
practical in nature, and not merely a theoretical subject. If at all 
Me, courses in soil bacteriology should include laboratory work 
along with classroom instruction. 

'I lie material which should he presented in the classroom and in the 
laboratory i-> the next question which should receive attention. It is 
nol intended to outline here the course as it is being taught, nor to 

venture t<< gay how it should he taught, hut merely to call attention to 
ome points which arc considered very important in connection both 

with the lecture work and with the laboratory exercises. 

In tlx- In 1 place, empha il ihould he placed upon the importance of 



BROWN : TEACHING SOIL BACTERIOLOGY. 



32/ 



a proper selection of the material to be presented and a clear sum- 
marization of the conclusions which the material warrants. Theoreti- 
cal considerations should be most carefully differentiated from definite 
facts. The separation of the wheat from the chaff is a difficult but 
very essential operation when preparing lecture material in soil bac- 
teriology. Not that there is so much questionable data on the subject, 
but that so many conclusions are little warranted and some methods 
of presenting the results of studies along this line are confusing, if 
not actually misleading. Some phases of bacterial action should be 
emphasized particularly, as, for example, nitrification and azotofication, 
while others such as deazotofication are minimized. The relation of 
bacteria to other elements than nitrogen should be considered at almost 
as much length as the bearing of the action of these organisms upon 
the nitrogen problem. Attention should be given to the carbon cycle, 
to the sulfur cycle, to the phosphorus problem, and so on. Mold action 
and the occurrence of protozoa and other organisms in the soil should 
be considered briefly. In short, the more essential phases of the sub- 
ject should receive major attention, while secondary theoretical prob- 
lems should be relegated to a minor place in the discussion. 

Again, the subject matter should be presented in such a way that 
the student can " tie it in " with his previous knowledge and correlate 
it with his agricultural experience. It should not be made too technical 
or too advanced, but given a practical turn or interpretation which will 
fix the principles in the student's mind. It is not nearly so essential 
that he remember the names and the life histories of a lot of soil 
organisms as it is that he obtain a new conception of the soil as a 
place where plant food is prepared and where proper bacterial action 
to a large extent determines crop production. Neither is it as impor- 
tant that he study the intricacies of the chemistry of bacterial action 
and interactions as it is that the common farm practices appear to him 
in a new light. Tillage, drainage, manuring, green manuring, liming, 
and other operations are presented from a new angle and it is by link- 
ing up the subject with such every-day practices that it becomes of the 
most interest and value. Such practical application of the principles 
involved need in no wise detract from the scientific accuracy of the 
subject matter, but will merely serve to bring it within range of the 
student's line of thought and make it of the greatest value to him in 
his life work. 

In connection with the laboratory work, the selection of the proper 
exercises is a matter of great importance. This selection must be based 
not only upon subject matter, but also upon adaptation to the student's 



3^8 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



previous training and upon the time available for the work. This 
latter factor is of special importance, as most exercises in soil bac- 
teriology must be handled at definite times, depending upon the neces- 
sary incubation period. Unless it is possible for students to work in 
the laboratory at other than the regular periods, the arrangement of 
the exercises should be such that the experiments are started at a cer- 
tain time and the determinations made at a specified period. It is also 
necessary, of course, that the total amount of work required shall fit 
in with the time permitted on the student's schedule. For this reason 
it is very desirable that the laboratory exercises be chosen most care- 
fully. The laboratory manuals on soil bacteriology which are available 
are all rather complete and it is improbable that all the exercises called 
for could be handled in one undergraduate course. A selection of the 
more important ones is therefore essential. It seems that these exer- 
cises should at least include the counting of bacteria and molds, the 
study of ammonification, nitrification, azotofication, deazotofication, and 
rhizofication. Cellulose fermentation and sulfur oxidation should also 
be included and the student should study the azotobacter, B. radicicola, 
and a few common soil organisms. With more time other exercises 
may very well be included, but one exercise along each of these lines 
will give the student a good fundamental working knowledge of the 
subject. 

in the case of the lecture work, it is very desirable that the 
laboratory exercises be given as much of a practical aspect as possible. 
Thi< may be accomplished by having the student work with certain 
definite soils and by requiring that at the completion of the course a 
write-up be prepared which shall contain an interpretation of the data 
secured. At tbe Iowa State College the students are urged to secure 
soil from their own home farms and to study the bacterial factor in 
those soils. Frequently the same soils are employed which are used 
in the fertility course and the student secures further knowledge of 
bis own soils. A maximum interest in tbe laboratory work is secured 
in this way. If it is not possible for a student to obtain soil from a 
farm in which be is interested, then he is required to study the soil 
from an experimental plat, on which definite treatments have been 
■•'I for some years and from which crop yields have been se- 
cured. It is usually considered preferable thai two soils be studied, 
ele ting those which have been differentiated by treatment and are not 

• it all alike ill Crop production. I'y making definite soils the basis of 
the laboratory work, and by insisting UpOll a full report and interpre- 
tation of the results, the work becomes real soil bacteriology and not 



BROWN : TEACHING SOIL BACTERIOLOGY. 



329 



a mere accumulation of bacteriological and chemical exercises, and the 
students derive the most possible value from the course. 

Almost a century ago Liebig declared that "agriculture is of all 
industrial pursuits the richest in facts and the poorest in their compre- 
hension." Soil bacteriology is facilitating to a wonderful degree the 
comprehension of agricultural facts and, as investigations progress, the 
accumulated observations of centuries are being subjected to a new 
scrutiny. Under the high power objective, as it were, they are ana- 
lyzed, sorted, classified, and interpreted. The facts which are con- 
stantly being brought to light at the present time in agricultural investi- 
gations are also being subjected to the same minute examination. 
While many of them do not at once come into focus and may for some 
time elude every effort toward interpretation, eventually they will all 
be explained. Soil bacteriology does more than provide a mere inter- 
pretation of observations, however. It leads to the recognition of new 
facts, it opens new fields of investigation, it permits the establishment 
of new practices, and it brings about the laying down of new princi- 
ples. Liebig once said. " Facts are like grains of sand which are 
moved by the wind, but principles are these same grains cemented into 
rocks." Soil bacteriology* is the cement which binds many agricultural 
facts into the hard rock of agricultural principles and practices. • 

In general, changing the simile again, it may be said that when 
properly understood and applied soil bacteriology is the microscope 
thru which agricultural science and farming operations appear more 
clearly and distinctly. With greater magnification or understanding 
of the subject, the more in detail will the picture of crop production 
appear. 

It is apparent, therefore, that if agricultural students are to receive 
a proper understanding of soils and crop growth, soil bacteriology 
must be taught in a special course, the proper material chosen for the 
course, and the subject tied in with agricultural practices. 



330 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



THE APPROVED SEED PLAN OF THE MISSOURI CORN 
GROWERS' ASSOCIATION. 1 

Roy T. Kirkpatrick. 

At the second annual meeting of the International Crop Improve- 
ment Association, held in Chicago on December I, 1920, it was shown 
that much work is being done in a number of States to stimulate the 
production of better seeds and to obtain a wider distribution of 
improved strains of high-yielding crop varieties. At this meeting the 
plans of several of the State seed organizations were explained and 
their work discussed. One noticeable thing thruout the meeting was 
that while all these organizations have a common purpose, the means 
used to bring about the desired results differ widely. In view of this 
fact it may be of some interest to note the plan now used by the Mis- 
souri Corn Growers' Association. The essential purposes of this plan 
are : 

1. To stimulate the production of better seed by members of the 

association. 

2. To test this seed and to put the association's official approval 
upon the best of it. 

3. To advertise officially the approved seed and in every way to 
promote its use. 

There is perfect cooperation between the Missouri Corn Growers' 
Association and the Field Crops Department of the College of Agri- 
culture, and only Mich crop varieties as have yielded high in tests con- 
ducted by the Field Crops Department are recommended by the asso- 
ciation and sold thin its approved list. 

The first work of the association is to stimulate interest in the use 
of pine seeds of high- yielding varieties thru educational work. This 

accomplished largely by means of a State corn show held in Colum- 
bia in January of each year, by various seed production and yield con- 

*• • and thru the work of the extension specialists in field crops, some 

of whom work with county agents and others with teachers of voca- 
tional agriculture in the Smith- 1 Inghes schools. The .association mem- 
bers are induced to secure the best seeds for planting and are then 

! Contribution from the Missouri Agricultural Kxpcrimcnt Station, Columbia, 
M<. Recetred for publication March 14, 1921. 



KIRKPATRICK : MISSOURI APPROVED SEED PLAN. 



331 



encouraged to have the seed they produce inspected, approved, listed, 
and advertised for sale by the association. 

In the case of all small grains, the fields are inspected by official 
representatives of the association just before harvesting time, for 
uniformity of the variety and freedom from disease and mixtures. 
If the field of grain comes up in quality to the high point set by the 
association, it is temporarily approved. After thrashing, a peck sam- 
ple of seed which represents accurately the average of the entire lot 
is sent to the secretary of the association to be examined for purity, 
uniformity, cleanliness, and germination. If this meets the desired 
standard, the lot from which it was taken is approved and the name 
of the grower placed upon the approved list of the association. Corn, 
soybeans, cowpeas, grasses, and clovers are not inspected in the field, 
the approval of these being based upon an examination of representa- 
tive samples of the lots of seed desired to be approved. For this pur- 
pose a 50-ear sample of corn, a peck of soybeans or similar seeds, or 
a quart of clover, alfalfa, or grass seeds is required. 

The approved seed list has a very wide distribution. It is mailed 
weekly to all members of the association, to all county agents and all 
teachers of vocational agriculture in the State, to the departments of 
agronomy of all colleges of agriculture in the United States, and is 
included in the weekly publication of the Missouri State Board of 
Agriculture. The list contains the names and addresses of growers, 
the varieties offered for sale by each, the quantity offered for sale, 
together with statements of its quality and in many cases the price per 
bushel desired. 

The seed approved is sold only under the official tag of the associ- 
ation, which tag complies with the Missouri seed law and gives the 
following information : Name of grower, kind of seed, varietal name, 
where grown, date tested, and percentages of germination, purity, weed 
seeds, and inert matter. 

One very important point should be noted. The responsibility for 
supplying seed equal in quality to the tested sample rests solely with 
the grower. The association recommends the seed of a grower whose 
sample meets the desired standard, but does not guarantee it. This 
principle is clearly stated on the official tag and on each copy of the 
approved seed list. There is, however, a legal as well as a moral obli- 
gation that seed sold under a tag that shows its quality must reach the 
standard of that test. This point is taken care of by the Missouri seed 
law, which compels the truthful labeling of all seed packages. 

The association makes no effort to fix prices on approved seeds, 



33^ 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



tho for the sake of completeness in the published list the grower is 
requested to state his price. This price is generally considerably lower 
than would have to be paid for the same quality of seed bought from 
the average seed house, but is high enough to pay the grower well for 
the extra expense* and trouble the sale has caused him. Of course, all 
trading is done directly between the grower and the buyer. The asso- 
ciation does not attempt to record all sales made or keep in touch with 
the men who buy thru the list, except in special cases, as where selected 
improved strains put out by the Field Crops Department are desired 
to be distributed over the State at large. Such sales are recorded and 
all buyers are kept in touch with until the seed has become widely 
distributed. . 

It will be seen that, unlike other seed associations, the Missouri Corn 
Growers' Association does not undertake the production and distribu- 
tion of limited quantities of " pedigreed " seed, nor does it undertake 
to sell thru a difficult and rigid system of certification. It does, how- 
ever, serve as an agency to distribute and increase superior strains 
produced by the Field Crops Department of the Missouri Agricultural 
Experiment Station. 

To the advantage of both the grower and the buyer, the farmers of 
this State are put in touch with large quantities of the best seed that 
can be found in Missouri. It is, therefore, the purpose of the asso- 
ciation not only to stimulate the production of good seed, but also to 
develop its approved seed project until the larger part of Missouri's 
crops are annually planted with the highest grade seed obtainable in 
the State. 

FREQUENCY AND IMPORTANCE OF FIVE-LOCK BOLLS IN 

COTTON. 1 

Henry Dunlavy. 2 

The varieties and strains of cotton found within the American Up- 
land group are characterized by having 4-lock and 5-lock bolls. Occa- 
sionally a 3- or a (\ lock boll is found, bU1 these are very scarce and 
of no i Otnmert ial importance. ( )f jo,2(>f> bolls of Acala cotton exam- 
ined l>\ the author only three 3-lock and two 6-lock bolls were found. 
I hese were all found within one pure-line strain. 

There if a well- founded partiality in the minds of the planters in 
favor of B ("Hon that producei high percentage of 5-lock bolls. 
This is reflected in the question often asked by growers, to which the 

'Received for publication July 29, [02X, 

m \irvv<Ur, Watson Cotton Seed Company, Waxaliachic, Texas. 



DUNLAVY : FIVE-LOCK BOLLS IN COTTON. 



333 



answer too frequently is : " This is a pure 5-lock cotton." None of 
the varieties of the American group produces 100 percent "fives," tho 
some varieties and strains undoubtedly have a tendency to produce a 
much higher percentage than others. Individual plants have been 
found that produce all 5s, but the plants produced from this seed were 
found to have some 4-lock bolls. 

The desire of the planter for a cotton that will produce a high per- 
centage of 5-lock bolls is well founded from the fact that they are 
heavier than the 4-lock bolls. From the weighing of 1,186 5-lock bolls 
and 725 4-lock bolls it was found that the 5-lock was 11.24 percent 
heavier than the 4-lock. From this it can be seen that the individual 
lock of the 4-lock boll is larger than that of the 5-lock, as the 5-lock 
contains 20 percent more locks and only about half this percent more 
weight. 

Table 1 shows the percentage of 5-lock bolls at the first, second, and 
third pickings. These data are from 24 rows of Watson Acala cotton 
grown in 1920 near Italy, Texas, together with the average for each 
picking, and the average for each row. Each row was planted with 
seeds from an individual plant selection in 1919. A total of 10,581 
bolls were studied, of which 7.764 contained 5 locks. 



Table i. — Percentage of ylock bolls at first, second, and third picking in Acala 
cotton, together with averages. 



Row. 


First picking. 


Second picking. 


Third picking. 


Average. 


1 


70.42 


76.34 


• 46.19 


62.97 


3 


95-37 


86.23 


81.94 


86.25 


7 


90.56 


84-54 


69.10 


78.82 


8 


88.88 


70.16 


54.28 


67.84 


9 


92.98 


84.78 


76.41 


84.88 


11 


93-44 


84-56 


64.61 


76.80 


12 


85.24 


62.82 


46.91 


56.97 


13 


77-55 


70.88 


56.00 


65-54 


14 


100.00 


94.24 


96.73 • 


95-88 


16 


88.23 


72.19 


65.29 


72.64 


19 


91.46 


86.98 


66.38 


80.98 


23 


80.00 


71.01 


57-89 


67.56 


24 


96.72 


91.74 


80.98 


88.91 


26 


96.05 


77-77 


61.29 


73-90 


30 


90.56 


85.00 


60.59 


73-79 


34 


82.05 


80.35 


62.33 


69.63 


39 


83.09 


82.74 


63.01 


75-46 


42 


91.22 


80.54 


66.38 


74-83 


43 


90.62 


76.39 


55-21 


66.93 


44 


87.41 


73-22 . 


66.96 


74.51 


45 


9I-I5 


76.61 


70.79 


78.92 


46 


64.19 


54.82 


39-97 


51-45 


48 


90.81 


85-53 


68.08 


80.65 


49 


70.73 


53-22 


.35-07 


52.49 


Average 


87.05 


78.19 


62.39 


73-38 



334 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



It is readily seen that, with two exceptions (numbers I and 14), 
the highest percentage of " fives " is found in the first picking ; the 
next highest in the second picking ; and the lowest percentage in the 
last picking. The first picking averaged 87.05 percent of 5-lock bolls, 
ranging from 64.19 to 100 percent. The second picking averaged 78.19 
percent of 5-lock bolls, ranging from 53.22 to 94.24 percent. The 
third picking averaged 62.39 percent of 5-lock bolls, ranging from 
35.07 to 96.73 percent. The average of all plants at all pickings was 
73.38 percent of 5-lock bolls, ranging from 51.45 to 95.88 percent. 

These results are very pronounced and tend to vindicate the producer 
in his persistent desire for a cotton that produces a high percentage 
of 5-lock bolls. 

HOME-GROWN AND IMPORTED RED CLOVER SEED. 1 

R. G. WlGGANS. 2 

On account of the very large importations of red clover seed during 
the past few years, the relative values of seed from different sources 
becomes very important. A test of red clover seed from three differ- 
ent sources was made at the New York State College of Agriculture 
in 1920. The results of the year's test are shown in Table I. 

The first and probably the most significant point in the table is the 
estimated stand after the first winter. The Italian-grown seed used 
in the test produce nonhardy plants for New York conditions, not 
having sufficient hardiness to withstand a mild winter such as that of 
1 920-2 r. The French clover was only slightly less hardy than the 
native grown. It should be said in this connection that a satisfactory 
growth was made during the first summer and that a perfect stand 
was secured in all plats. 

All weights given in the table are actual dry weights as determined 
by drying 20-pound samples to dryness. The differences in the yields 
1 orregpond very closely to the estimated stand, altho the green weight 
of the brcnch type was relatively higher, due to its being a little larger 
and later. This was shewn also by its smaller percentage of dry 
matter. 

I he results of this seeding, therefore, indicate that red clover grown 
from Italian Seed winterkills easily under New York conditions, and 

that it ; omewhal doubtful if seed from France should be used if 

native -jjrown seed can be obtained. 

I ►ntrihution fi in the Cornell University Agricultural Experiment Station, 
hli.va, X. Y. Receiver! for publication November 4, 1921. 
2 A*tifttant professor of farm crops, Cornell University. 



WIGGANS: HOME-GROWN AND IMPORTED RED CLOVER SEED. 



Table i. — Winter survival, dry weights per plat, and other data obtained from 
clover grown from native, French, and Italian seed at Cornell University in IQ20 
and IQ2I. 



Source of seed. 


Estimated 
stand 
after 
first 
winter. 


Dry weight 
First cutting. 


.s per plat. 
Second cutting. 


Drv 

isl y 

weight 
per 
acre 
for 

season. 


Estimated 
percentage 

of total 
yield as 

clover. 


Drv 

isi y 

weight 

of 
clover 

per 
acre. 


Series 1. 


Series 2. 


Series I. 


Series 2. 




Percent. 


Pounds. 


Pounds. 


Pounds. 


Pounds. 


Pounds. 




Pounds. 


Native 


















(Mich, grown) 


90 


52.8 


57-1 


30.4 


27.7 


6,770 


98 


6,635 




80 


49.9 


50.3 


29-3 


22.7 


6,088 


98 


5,966 


Italian 


5 


21.3 


18. 1 


24.0 


20.2 


3.344 


10 


334 



AGRONOMIC AFFAIRS. 

TORONTO MEETING OF THE SOCIETY. 

A program meeting of the American Society of Agronomy will be 
held on December 29, 1921, at Toronto, Ontario, in connection with 
the meeting of the American Association for the Advancement of 
Science which will be held there during the week beginning Decem- 
ber 26. On the preceding afternoon, December 28, the meeting of 
Section O (Agriculture) of the association will be held, and on the 
evening of December 28 Section O and the American Society of 
Agronomy will have a joint dinner at a place to be announced during 
the session. All members of the Society who can attend these meet- 
ings, especially all members in Canada, are urged to do so. A cordial 
invitation is extended to Canadian agronomists who are not now mem- 
bers of the Society. 

MEMBERSHIP CHANGES. 

The Society continues to show a slow but steady growth. The num- 
ber of members previously reported was 647. Since that report was 
written 7 new members have been added, 1 has been reinstated, 1 
member has resigned, and 1 member has died, making a net gain of 6 
and a present membership of 653. An encouraging fact is that the 
library subscription list, and particularly the foreign list, is constantly 
growing. 

NOTES AND NEWS. 

C. D. Davis has been appointed assistant professor of farm crops 
at the Kansas college. 



336 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Alva C. Hill has been made assistant in field crops at the University 
of Missouri. 

Kristen Skovgaard, who has been engaged in postgraduate study at 
Iowa State College and at Cornell University during the past year and 
a half, has returned to Denmark and is now located at Frennegard, 
Harshblin. 

A. E. McClymonds, formerly extension agronomist in Colorado, is 
now superintendent of the Aberdeen (Idaho) substation. 

M. A. Beeson has been elected dean of the college of agriculture of 
Oklahoma, and C. T. Dowell has been made director of the experiment 
station. \Y. A. Conner is now director of extension in that State. 

Dr. John L. Coulter, for the past several years dean and director of 
the West Virginia College and Station, has been elected president of 
the Xorth Dakota Agricultural College, and has entered on his new 
duties. 

W. H. Dalrymple has resigned as director of the Louisiana station 
on account of ill health, and was succeeded on October 10 by W. R. 
Dodson. who resigned from this position about a year ago to engage 
in commercial work. 

G. F. Freeman, for the past three years cotton breeder for the 
Societe Sultanienne d* Agriculture at Cairo, Egypt, is now chief of the 
division of cotton breeding at the Texas station. 

David Friday, professor of economics and finance at the University 
of Michigan, has been appointed president of the Michigan Agricul- 
tural ( 'ollege. effective January 1. F. S. Kedzie, the retiring president, 
has been made dean of the department of applied science. 

P. L. Gile, formerly associated with the American Agricultural 
Chemical Co., is now in charge of the soil chemistry investigations of 

the Federal Bureau of Soils. 

J. \V. Gilmore, professor of agronomy in the California College of 
Agriculture, has returned from the University of Chile, where he has 
been c\< lian^e professor for the past six months. 

J. B. Thompson, specialist in forage crops at the Florida station, 

resigned August to become agronomist in charge of the Virgin 
Islands Kxperinicnt Station. 

I I Thornber, professor of botany in the University of Arizona, 
UCCCCded I). W. Working as dean and director of the agricultural 
college and stat ion oi that institution on September f. 



JOURNAL 

OF THE 

American Society of Agronomy 



Vol. 13. December, 1921. No. 9 



THE AGRONOMIC PLACEMENT OF VARIETIES. 1 

C. A. Mooers. 2 

Both the botanist and the agronomist are interested in plants, but 
their points of view are different. The principal interest of the bot- 
anist lies in taxonomy, histology, physiology, or some subject other 
than the productiveness of the plant, whether of foliage or fruit. To 
the agronomist, on the other hand, production, or yield per unit area, 
is the fundamentally important consideration. The agronomist, there- 
fore, pays much attention to varieties, with regard to both yield and 
quality of product and to the means whereby they may be improved. 
He also gives special heed to numerous other factors which affect yield, 
such as time and rate of seeding, soil preparation and adaptability, 
fertilizers, and soil bacteria. Thruout, crop yield is the central thought 
and is, in fact, the tie that binds agronomists together. 

Every branch of science goes naturally thru certain stages of de- 
velopment. There is the preliminary gathering of data and their 
assembly to try out various hypotheses, and in time the subject is 
placed on a scientific basis with attendant theories, mathematical 
formulas, etc. Agronomy has been defined as that branch of agri- 
culture which treats of the theory and practice in the production of 
farm crops. This definition appears to fit the present situation, for 
agronomy as the science of crop yield has advanced little beyond the 

1 Presidential address of the American Society of Agronomy. Presented 
before a joint session of the American Society of Agronomy and the Society 
for the Promotion of Agricultural Science at New Orleans, La., November 
8, 1921. 

2 Agronomist and vice-director, Tennessee Agricultural Experiment Station, 
Knoxville, Tenn. 

337 



33S 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



data-gathering- stage. As long as this is true it remains under a cer- 
tain ban. Devotees of so-called pure science speak lightly of it. Stu- 
dents complain of the many exceptions and precautions and of the 
general lack of solid foundation. Such a condition puts the agron- 
omist on the defensive and makes his subject less attractive to those 
who might specialize in it. However this may be, I am sure that every 
advance toward a scientific basis is welcomed by all. I will go a little 
farther and say that I believe the time has come, first, for the improve- 
ment of certain of our methods of field experiments with a view to 
scientific accuracy; second, for progress in getting agronomy onto an 
exact, or mathematical, basis. I have especially in mind a subject that 
has often been looked upon with distrust or considered as' a sort of 
necessary evil. I refer to varietal experiments. 

The American farmer produces annually crops valued into the bil- 
lions of dollars. A very slight percentage increase would under usual 
conditions result in a large increase in aggregate value. The experi- 
mental agronomist has full faith in the superiority of certain varieties 
over others. Thru the Division of Extension and other agencies he 
has great influence in determining the variety the farmer shall grow. 
The setting is right, therefore, for the practical application of what 
appear superficially to be plain, simple data from the apparently simple 
varietal experiments. On the other hand, it is not difficult to find good 
support to the view that for large sections of the country it is a ques- 
tion whether the yields would be increased or diminished were the 
farmers to follow so-called authoritative advice in the choice of va- 
rieties for some of our staple crops. In the study of bulletins on corn 
the writer has been impressed with the fact that authors are inclined 
to draw their main conclusions from only the more recent experiments, 
the inference being that the old data are unreliable, or, so to speak, 
out of date. At the Xorth Carolina station the writer was told that 
varietal trials, as conducted in the past, had been discontinued because 
considered to give information that was more or less misleading. In 
their place special attention was given to corn improvement in com- 
munities thru cluba which Utilized the best local varieties. Varietal 
trial were conducted, bu( with regard only to local conditions, the 

i ommunit) < lub being the chief, or final, judge of the results obtained. 
Ihc following statement is made by Carrier:'' 

\ /o.e many experiments with corn have Urn conducted, and the pub- 
lish' d n nit- arc voluminous. It is very disappointing, however, to try to 

'•i Lyman. A rca-.n for the contradictory results in corn experi- 

ni'iits hi Joi n. Amir, Sn< . Aonon., v. n, no. 3, p. kk;. i 919. 



MOOERS: AGRONOMIC PLACEMENT OF VARIETIES. 339 



summarize these data, especially if the results are given in terms of grain. 
The summary often presents a quantity not sufficiently positive or negative to 
prove anything. 

Iii explanation of the unreliability of varietal trials Carrier lays stress 
on the effect of xenia, and presents evidence to show that kernels 
resulting- from cross pollination between varieties are, as a rule, ap- 
preciably heavier than the others and may materially affect the outcome 
of a trial. Both the teachings on the subject of varieties at our leading 
universities and agricultural colleges and the facility with which bulle- 
tins on varietal trials find the waste basket point to a lack of confidence 
in work of this character. This situation is to our discredit as agron- 
omists, and the removal of the charge would do much toward increas- 
ing our standing not only with other scientific workers, but also with 
the farmer. 

I now face the difficult task of attempting to outline the essential 
requirements in the placing of our agronomic knowledge of varieties 
on a scientific basis. I have in mind a basis which will, for example, 
allow a mathematically accurate selection of a variety for a given set 
of conditions, enable us to tell closely the number of days to maturity 
from a given date of planting, and calculate exactly the best number 
of plants per acre for the highest yield and best quality of product. 
I do not pretend, however, to have solved all of the problems involved, 
but I shall try to establish some new points of view and to indicate 
certain features which appear to me to be essential to the successful 
solution of the problem as a whole. 

For various reasons, but chiefly because of having at hand a fairly 
large amount of data, I have taken varieties of corn as an example. 

Sources of Error in the Conduct of Varietal Experiments with Corn. 

I desire to call your attention briefly to the more important sources 
of error, as I see them, in the conduct of varietal trials, for trust- 
worthy field data are of fundamental importance in the solution of 
our problems. 

NUMBER OF EXPERIMENTAL PLATS. 

All agronomists will agree that uniformity in soil productiveness is. 
highly important. Unfortunately most of us have found that it is 
hard to get. The experimental tract can be manured, plowed, and 
prepared in a uniform manner; the planting, cultivation, and harvest- 
ing can be done so as to be fair for all varieties ; but the natural in- 
equalities of the soil prove a source of error to be overcome. There- 



340 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



n fore, replications are required. The number is debatable, but I will 
suggest three ; that is, three plats for each variety in the series are 
needed in order to judge its comparative value as a grain producer. 

NECESSITY OF THE RIGHT STAND FOR EACH VARIETY. 

Some years ago I called attention to the importance of the proper 
adjustment of the stand to suit the special requirements of every 
variety. 4 Data obtained since then emphasize the importance of this 
factor, as may be seen in Table I from trials on fertile bottom land at 
the Tennessee station at Knoxville. 



Table i. — Average yields per acre of typical varieties of corn at each of three 
rates of planting from twelve crops grown from 1906 to 1915- 



Variety. 


6,000 plants. 


8,000 plants. 


10,000 plants. 


Grain. 


Stover. 


Grain. 


Stover. 


Grain. 


Stover. 




Bushels. 


Tons. 


Bushels. 


Tons. 


Bushels. 


Tons. 




70.9 


2.44 


69.6 


2.60 


68.1 


2.78 




68.4 


331 


64.O 


3.3i 


60.4 


3-77 




55-5 


1.83 


61.9 


2.07 


69.4 


2.32 



Tn this table are shown the results from three typical varieties : 
1 1 liftman. Albemarle, and Hickory King. Along with Huffman would 
be included a number of large late-maturing varieties, such as Shaw 
Improved and Higgs. With Hickory King would be grouped Boone 
County White, Reid Yellow Dent, Piedmont White Dent, and many 
others. With Albemarle arc found Cocke, Marlboro, and other true 
prolifics, which have a marked adaptability to rather wide variations in 
rate of planting, or stand, without change in the grain yield as indi- 
cated in Table 1. 

Had only the 6,000 rate been used, the logical conclusion would be 
that Albemarle was first in grain yield, that Huffman was a close 
second, but that Hickory King was far outclassed by the other two. 
\t tlieX.ooo rate Albemarle is easily first ; Huffman is second, with an 
BVCragC production of 5.6 bushels less than Albemarle; and Hickory 
King il third, but only 2.1 bushels per acre less than Huffman. At 
1 1 . 10,000 rate Hickory King is first, Albemarle a close second, yield* 
I , bu hels less, and Huffman a poor third, lacking 9 bushels per 

acre, on the average, of equaling Hickory King. With examples like 

M 1 \ m;uk1 ;m<l oil fertility as factors in the testing of varieties 

of <orn. Trim. A«r. Kxpt. Sta. Hul. 89. 1910. 



MOOERS : AGRONOMIC PLACEMENT OF VARIETIES. 



341 



these before us, and they are typical of many that could be cited, are 
we not warranted in saying that the rates of planting in a varietal trial 
must, conform to the requirements of each individual variety? Since 
this is generally unknown, several rates of planting so as to cover the 
possible range of requirements are usually necessary. 

number' of rows per plat. 
The number of rows per plat is another item that deserves more 
attention, but I have no special evidence on the subject. At some sta- 
tions very narrow plats, with only one or two rows, have been used. 
If varieties of widely different habits of growth be planted side by 
side, shading effects, detrimental to the smaller variety, would be ex- 
pected. This and other sources of error could be reduced by the use 
of, say, 6-row plats with an extra outside, or guard, row on each side. 

DURATION OF TRIAL. 

The duration of the trials is an important matter that has not been 
settled. Results given in a recent Missouri bulletin 5 show that eight 
years were required in some series in order to establish the relative 
order of yield of the varieties grown. The value of methods which 
would cut down the time required B to reach reliable conclusions is 
evident. 

THE VALUE OF A CONSTANT STANDARD VARIETY. 

The value of a fixed standard variety, and not a fluctuating standard, 
due either to changes brought about by selection and breeding or to 
widely different sources of seed, appears not to be fully recognized. 
For reasons that will be presented later, I believe that the standard 
variety should receive the same strict attention by the agronomist as 
the standard acid by the analytical chemist. 

Locality and Soil Productiveness in the Interpretation of Data. 
In the discussion of data from varietal trials the general and almost 
universal point of view is locality; that is, if a certain variety gave the 
best yields at a certain place, it is assumed to be especially adapted to 
the climate and soils of the surrounding country. As a rule, a State 
is divided into large districts, and the varieties recommended for each 
are those that have given the highest yields under, perhaps, only one 
soil condition ; that is, the soil may have been rich, medium, or poor 

5 Stadler, L. J., and Helm, C. A. Corn in Missouri. Mo. Agr. Expt. Sta. 
Bui. 181. 1920. 



342 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



as to productivity. If the soil happened to be typical of the whole 
district, the conclusion reached may be justified; but if the soils of the 
district differ widely in productivity, or if the soil used in the experi- 
ments be either much better or much poorer than the average, what 
then ? 



Productivity 
in bushels 



60 



50 



60 40 



50 30 



40 60 20 



30 50 



20 40 



30 



20 

















/ 

Y 








* 






/ 


/ / ' 
/ / 




/ 


~^~7 

/ / 


/ 

/ 

/ y 




/ / 
/ / ' 




/ 

/ 


/ / 

/ s 




/ 


/ y/ 
/ / 

/ s 


/ 


/, 


7^-7 

/ / 

/ / S 


y 

s 






S 






s 









Identical 

Superior parallel 
Inferior parallel 
Superior divergent 

Inferior divergent 



1 2 3 4 5 

(16-35 (16-35 (3 r >-45 (46-55 (56-65 
bu.) bill Ixi.l 1)11.) Oil.) 



( 1 roup 



Fig. 17. Hypothetical relationships between varieties with respect to yield 

as induced l»y varying devices of soil productivity. 

SOMl EiYFOTBBTK \L Vaki 1 1 ai. RELATIONSHIPS, 

I '''< !it study of data obtained at the Tennessee station during the 
' 1 ytMA I11 COnvinceo 1 me thai we innst consider the relative 
Standing "i varieties from what I believe to be a new point of view, 



MOOERS : AGRONOMIC PLACEMENT OF VARIETIES. 



343 



which I have had the pleasure of developing for this occasion. First 
I outlined some hypothetical relationships between varieties of corn as 
grain producers on soils of various degrees of productivity. To illus- 
trate them I have prepared figures 17 and 18, in which the ordinates 



Productivity 
in bushels 



60 



50 



60 



50 



40 



30 



40 60 20 



30 50 



20 40 



30 



20 





















/ 




/ / 



/ 


y 

/ 

/ 


/ / 

^— y: 


/ 

/ 




s / 
/ / 

— 


/ 




' / 
/ 

f ' 


/ 

/ ' 

y 







/ / 

t 


/ / 










// 

4< — 






JT / 








~f 

/ 

/ 









Superior convergent 
Inferior convergent 



Superior intercept 
Inferior intercept 



12345 Group 

(16-25 (26-35 (36-45 (46-55 (56-65 
bu.) bu.) bu.) bu.) bu.) 



Fig. 18. Hypothetical relationships between varieties with respect to yield 
as induced by varying degrees of soil productivity. 



show soil productivity conditions in terms of grain per acre and the 
abscissas show averages from group yields for soils of various degrees 
of productivity. As arranged the groups are 15-25 bushels, 26-35 



544 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



bushels, etc., based on the yield made by the standard variety. If the 
trials be numerous enough, the curve for the standard variety will by 
the conditions be a straight line passing as shown thru the intersections 
of the coordinates. Now, let the yields made by another variety in the 
same series of experiments be grouped, not according to the conditions 
laid down for the standard, but according to the yields obtained regard- 
less of size. For example, if the standard makes, in a 5-year trial on 
a poor soil, yields between 15 and 25 bushels per acre, with an average 
of 20 bushels, another variety tested in the same series might make an 
average of, say, 26 bushels ; and tho the majority of the yields might 
have been more than 25 bushels, the point would be located on the 
group 1 ordinate. In a like manner a point would be located for each 
of the other groups. The question now arises as to the form of the 
curve of a variety grown in comparison with the standard. Let us 
assume it to be a straight line. There are then the following possi- 
bilities, provided the standard is a medium yielder. 

1. A variety making yields which under all conditions are practically 
identical with those made by the standard. Such a variety I have 

signated, with reference to the standard, as an identical. 

2. A variety outyielding the standard by a nearly constant amount 
under widely different conditions of productivity I have designated as 
a superior parallel. 

3. In a similar manner a variety might be an inferior parallel, be- 
cause surpassed by the standard by a nearly constant quantity on all 
kinds of soils. 

4. A variety surpassing the standard under all conditions, but the 
difference between them increasing with an increase in productivity, 
1 have designated as a superior divergent. 

5. In a similar manner a variety might be an inferior divergent 
because surpassed by the standard, the difference increasing with the 
increase of soil productivity. 

6. A variety surpassing the standard under all conditions, but to the 
< .»'< 1 extent under conditions of low yield, I have designated as a 

superior convergent. 

7. An inferior variety showing its widest divergence under poor land 
Condition . but tending to approach the standard under rich land con- 
ditions, would be ;m inferior convergent. 

S. \ variety superior under conditions of low yield, but inferior 

tinder < onditions of high yield, I have designated a superior intercept. 

'/. A variety inferior under conditions of low yield, but superior 
under conditions of high \ ield, \ designated .'in inferior intercept. 



MOOERS: AGRONOMIC PLACEMENT OF VARIETIES. 



345 



Experimental Evidence. 
Let us now notice the results bearing on this subject obtained in 
experimental trials conducted in various parts of Tennessee. In these 
comparisons, however, no distinction was made between yields due to 
the favorableness or unfavorableness of a season and those due to the 
degree of productiveness of the soil under average conditions ; that is, 
the curve for the standard was determined by averaging all the yields 
obtained within the group limit, regardless of whether the soil or the 
season was the prominent factor in bringing about the yield obtained, 
or both soil and season. Differences in soil productivity were, how- 
ever, the chief cause of the variation. Table 2 and figures 19 to 23 
show the results obtained in the longest continued and nearest complete 
experiments. In this connection it should be noted that the experi- 
ments were made in various parts of the State, including east, middle, 
and west Tennessee, and at elevations from 360 to 1,850 feet. Prac- 
tically all the very high yields were obtained at the Knoxville station, 
on rich bottom land. The very low yields nearly all came from the 
Cumberland Plateau and the Highland Rim of middle Tennessee. The 
medium yields come from various localities over the entire State. In 
these trials Hickory King, a medium yielding variety, of easy identi- 
fication and well established in the State, was used as a standard and 
is shown as the solid line in the figures. 



Table 2. — Results from varietal experiments with corn in Tennessee sum- 
marized with regard to yields of grain in bushels per acre. 0. 





Group, determined with regard to Hickory King 
as a standard. 


Variety. 




2 


3 


4 


5 


6 


7 




(10-25 


(26-35 


(36-45 


(46-55 


(56-65 


(66-75 


(76 




bu.). 


bu.). 


bu.). 


bu.). 


bu.). 


bu.). 


bu. up). 




22.3 10 


30.7 16 


3Q-8 34 


49. 4 15 


57-I 8 


68.6 2 


80.62 




21.5 10 


27. o 16 


3I-9 34 


43-I 16 


49.18 


56.82 


6 7 -4 2 


Hickory King 


22.7° 


28.7 7 


41. 2 16 


50.5 7 


55-2 1 


6o.6 2 


76.6 2 


Neal Paymaster 


26.0 6 


35-I 7 


49-3 16 


58.6? 


69.9 1 


78-3 2 


95.0 2 


Hickorv King 


22.3 10 


30. o 13 


41.4 16 


50.7 7 


58-9 6 


69-2 4 


78.6*' 




20. 9 10 


30.7 13 


45.1" 


54-4 7 


65-5 6 


73-3 4 


93.2" 


Hickory King 


22. 4 8 


29-5 7 


40.6' 4 


50.9 5 








Piedmont White Dent .... 


27.8 8 


37-0 7 


43 -3 14 


52-3 8 








Hickorv King 


22. 8 5 


3i-0 9 


39.8 26 


49.8 8 


58. 8 10 


69.2* 


78. 6 8 




21. 1 5 


27.08 


40.9 26 


48. o 8 


57-3 10 


68. 8* 


90.7 6 



a Superior figures show the number of trials averaged. 



346 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Figure 19 shows that Learning, in comparison with Hickory King, 

is an inferior divergent — that is, it yields less than Hickory King under 

all degrees of productivity — but as the soil productivity increases the 

Soil 
produc- 
tivitv 
bu. 



70 

60 

50 

40 

30 
20 





















/ 

/ 

/ 


— ^ — 








y 








/ 


s 










/ 

/ 












/ 













Group 



12345 67 
Fig. 19. Comparison of yields of Learning and Hickory King. 

Soil 
produc- 
tivity, 
bu. 

90 



80 
70 
60 
50 
40 
30 
SO 













/ 












— A- 

/ 

/ 

/ 










/ 

' s 

s 










/ 

/ 










/ 

/ 










/ 

/ 

/ 










/ 


— y — j 










/ 













( iron 1 ) 



133450,7 

( omparison ol yieldi of Neal Paymaster and Hickory King. 



greater if the difference between the yields of the two varieties. Fig- 
rj shows that N'cal Paymaster behaves as a superior divergent to 
Hickory King, because as the soil productivity increased the greater is 



MOOERS: AGRONOMIC PLACEMENT OF VARIETIES. 



347 



its lead. Figure 21 shows that up to a production of about 28 bushels 
Albemarle is inferior to Hickory King, but thereafter it is superior. 
In other words. Albemarle as compared with Hickory King is an in- 



Soil 
produc- 
tivitv. 
bu. 

80 






















1 

1 


70 












/ 

/ J 
/ / 


60 








/ 


/ A 
/ / 




50 






/ 

S + 


7— 

/ y 
/ / 






40 




i 
/ 1 


/ / 








30 




/ / 
/ / 
// 
// 










20 


/ 













1234567 Group 
Fig. 21. Comparison of yields of Albemarle and Hickory King. 



Soil 



50 



40 



21 ) 











y 


y/ 
y / 


/ 

/ 

/ 


s / 
y / 




—/■ 







12 3 4 Group 

Fig. 22. Comparison of yields of Piedmont White Dent and Hickory King. 

ferior intercept. In figure 22 Piedmont White Dent appears to be a 
continued, but unfortunately without regard to the best rate of planting 
superior convergent as compared with Hickory King. In figure 23 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Huffman is compared with Hickory King. The comparison was long 
for each variety. The information is now available to show that Huff- 
man should be planted relatively thin and Hickory King relatively 
thick. This may account for the lack of a more positive direction for 
the Huffman curve. Probably this variety is an inferior intercept as 
compared with Hickory King. On the other hand, should the peculiar 
form of the curve obtained be verified by later experiments, locality 
adaptability would seem to be indicated. Results like these can not be 
attributed to chance. The curves conform too closely to straight lines 

Soil 
produc- 
tivity, 
bu. 

80 



70 
60 



50 
40 

30 
20 

1 2 ' 3 4567 Croup 

Fig. 23. Comparison of yields of Huffman and Hickory King. 

for that. I conclude, therefore, that the data at hand are very strong 
evidence thai one variety may bear toward another any one of the 
simple relationships indicated in the nine hypothetical relationships; 
thai IS, the curve showing the relationship as to grain production be- 
tween one variety and another, taken as a standard, approaches a 
Straight line and has a definite position with regard to a standard. 
This < on< In ion is of greatest importance wherever the growing season 
is long, permitting widely different varieties to mature. I ne experi- 
mental wr.ii entailed in the determination of varietal place should not 

" ■ ■ ei i! oh taele, becau c only two serifs of experiments arc 
needed, VIZ . one On rich land and one on poor land, for in this way 

the two points necesiar) to locate a straight line would be obtained. 













1 

/ 

/ 












/ / 
1 / 




















/V 
// 
// 












/ 








// 
' / 












/ 











MOOERS : AGRONOMIC PLACEMENT OF VARIETIES. 



349 



I can not refrain from calling attention to the fact that the usual 
assumption implied in varietal bulletins up to the present time is that 
a variety is either an identical, a superior parallel, or an inferior paral- 
lel, no attention being given to any of the other six possibilities. I 
see no special reason why any of the first three relationships should 
occur oftener than any of the others. 

Also I will digress to call attention to the large error that may be 
produced in field experiments by changing from a soil of low produc- 
tivity to one of high productivity, if the yields from both are to be 
about, for instance, by the heavy manuring of the experimental range 
gathered under a single average. Such a condition could be brought 
which was previously of low or moderate productiveness. This heavy 
manuring, coupled with a single very favorable season, might easily 
throw the result as a unit series entirely out of joint and lead to very 
erroneous conclusions. 

The Date of Maturity of a Variety. 

An accurate method of calculating the date of maturity of a given 
variety when planted at a given time and place is desirable in farm 
practice, especially in the South, where the period of planting extends 
over three or even four months. Figures 24 to 26 show the curves 
plotted from the results of date-of-planting experiments conducted for 
some ten years at the Tennessee station for each of three distinct 
varieties of corn, Learning an early, Hickory King a medium, and 
Huffman a late maturing variety. By the aid of these curves the 
probable date of maturity for any date of planting is easily deter- 
mined. I wish to call attention to an interesting feature of these 
curves. They appear to be not only arcs of a circle, but of a circle 
having the same radius, but with differently located centers, as may be 
seen in figure 27. The curves were plotted separately on coordinate 
paper and without any thought at the time that they would prove to be 
arcs of a circle, not to mention of the same circle, but when super- 
imposed the three curves were found to coincide almost perfectly and 
to form the arc of a circle having a radius nearly nine times the length 
of one of the coordinate squares of the system shown in the figures. 
It remains, of course, to be determined over what geographical limits 
this finding is substantially true. It is possible that dates of planting 
and maturity as obtained in the usual varietal trials might be utilized 
in the locating of this arc with sufficient accuracy for practical purposes. 



5 50 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The Productive Vigor of A Variety. 

Another important factor relating to the placement of varieties needs 
to be determined, and that is what I will call the comparative produc- 
tive vigor of a variety thruout its possible climatic range. So far as 
I am aware, this problem has not been seriously investigated, but I 
believe it capable of satisfactory solution. The indications are that a 
variety will have similar rating over a large area. At any rate, many 
could be mentioned whose high yielding capacities are not limited by 
the boundaries of several States, not to mention counties in a State, 



Date of 
planting 

July 




Fig. 24. Maturity graph for Learning. 

bill there are probably limitations other than mere length of season and 
general productivity conditions. I refer to the effects of such factors 
length of flay, temperature, and humidity of the air to the physio- 
logical peculiarity of a variety and to the physical character of the soil. 

Summary. 

In conclusion, I will Summarize the situation as follows. The fourth 
paragraph of the lummary relates, however, to a matter barejy men- 
tion* : : I'. , Inn is germane lo the general subject. 

1. Certain improvements are needed in the conduct of varietal trials 

with. 1 i to cientift accuracy, tncreased attention should be given 



MOOERS : AGRONOMIC PLACEMENT OF VARIETIES. 



351 



to at least the following points : 

a. The proper stand for each variety. 

b. The importance of a standard variety. 

Date of 
planting 

July 



June 



.Max- 



April 



March 




Days to 

100 no 120 130 140 160 maturity 

Fig. 25. Maturity graph for Hickory King. 



Date of 
planting 

July 



June 



May 



April 



March 




120 
Fig. 26 



Days to 
maturity 



130 . 140 150 

Maturity graph for Huffman. 

c. The necessity of conducting varietal trials on soils which are truly 
representative of productivity conditions of the region to which 
the results are to be applied. 



352 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



2. Nine simple relationships appear to exist between varieties of 
corn with regard to grain production on soils differing in productive- 
ness. The location of varietal curves with reference to a standard will 
make possible better founded and more accurate selection of a suitable 
variety for a given condition. 

3. Data from date-of -planting experiments enable the plotting of a 
curve by means of which the approximate date of ripening of a variety 
can be predicted with a fair degree of accuracy. All three of the 
curves obtained, one each from an early, a medium, and a late maturing 
variety, appeared to be arcs of a circle with the same radius, but with 
different centers. 

4. A practical method* 3 of calculating the most favorable number of 
plants per acre has been worked out, the variety to be grown and the 
productiveness of the soil in the average season being the factors taken 
into consideration. The range of its adaptability and all necessary 
modifications to give it wider application need to be determined. 

5. There remains to be determined in particular the productive vigor 
of every important variety over its possible territorial range. With 
this factor in hand we would, as I am viewing the subject, be able to 
say that a scientific basis for the agronomic placement of varieties not 
only of corn but of other crops was on the high road to successful 
completion. 

Date of 
planting 



May 

















\. 6 



































nxi [10 130 i.V> 1 j< > 150 160 maturity 

J i'. .7. < mparahlc location of maturity graphl fof three varieties of corn. 

• Mooers, C. A. PUntinf rattl Mid spacing of com under Southern condi- 

/" I"' »' \.MIH. So( . A '.HON., V. 12, JIO. I, p. I 22. 1Q20. 



HARTWELL \ CROP RESPONSE TO FERTILIZERS. 



353 



RELATIVE GROWTH RESPONSE OF CROPS TO EACH FERTI- 
LIZER INGREDIENT AND THE USE OF THIS RESPONSE 
IN ADAPTING A FERTILIZER ANALYSIS TO A CROP. 1 

Burt L. Hartwell. 2 

Before considering the special needs of the various crops brief refer- 
ence should be made to the different progressive, or perhaps retro- 
gressive, agricultural conditions under which crops in general have 
obtained the food absorbed from the soil medium. 

The farmer first solved the problem of crop feeding by selecting 
virgin soil from which the roots could secure the entire needs of the 
plants. Later he learned that it was better practice to spread on the 
land the refuse from his animals than to dump it into the river. He 
was slow to admit that the soil of his choice could possibly deteriorate, 
but, instead, he delighted in advertising the inexhaustible fertility of 
his broad acres. 

The failure of certain crops to yield as much as formerly has led to 
their production on newer lands by the next group of pioneer farmers. 
x*\s the population increased around his farm he has been willing to 
accommodate the livery stables by removing their refuse from time to 
time and spreading it on his land. He might be persuaded to use a 
little lime or some source of phosphorus with his manure, but he 
wanted you to distinctly understand that fertilizers were absolutely 
unnecessary in his favored locality. 

Having finally learned to recognize the value of animal manures, per- 
haps even to the extent of conserving them, it was a rude shock to 
find that one source of animal manure was gradually being replaced by 
other methods of locomotion which unfortunately yielded no valuable 
by-product for his land. A little fertilizer in the drill then came to be 
recognized as a useful " stimulant," to be applied sparingly, however, 
lest it poison the soil. 

Slowly the idea spread that some soils were actually deficient in one 
or more nutrients, and the general public still holds firmly to the belief 

1 Presidential address of the Society for the Promotion of Agricultural 
Science. Presented at a joint session of that Society and the American Society 
of Agronomy at New Orleans, La., November 8, 1921. Contribution 284 of 
the Agricultural Experiment Station of Rhode Island State College, Kingston, 
R. I. 

z Director and agronomist, Agricultural Experiment Station of Rhode Island 
State College. 



3 54 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



that it is only necessary to analyze the soil before plai nig in order to 
find out just what fertilizer is needed to supply those ieficiencies. It 
has not occurred to the public that the contributions which mother earth 
makes are tremendously influenced by the weather, an< 1 that until this 
can be predicted satisfactorily the chemist can not b.e expected to tell 
what will be needed to supplement its immediate effects. 

In deciding upon the general composition of fertilizers the manu- 
facturer was influenced by the fact that the soil, as well as the animal 
manures which his mixture was to supplement, contains a relatively 
small amount of phosphorus. These considerations and the cheapness 
of sources of this element led to a very liberal proportion of phos- 
phorus in the fertilizers. Four to five times as much of this ingredient 
as the crop removed has been used, and economically, too. 

In their relation to the rapidly disappearing manure, fertilizers must 
be looked upon more and more as substitutes rather than supplements. 
A 4:8:4 fertilizer (that is, 4 percent of total ammonia, 8 of "avail- 
able " phosphoric acid, and 4 of water-soluble potash) has been popular 
where more or less manure was to be had. When it is recalled, how- 
ever, that, on the basis of total ingredients, 5 tons of manure represent 
a 6:3:5 fertilizer, it seems probable that, to replace entirely the highly 
ammoniacal and potassic animal manure, fertilizer analyses will be 
changed materially and the ammonia and potash be increased relative 
to the phosphoric acid. As a general relation 2:4:2, for example, may 
be changed to 2:3:2. 

It seems probable that the current practice of applying phosphorus 
far in excess of what the crop removes will eventually modify the soil 
BO that the deficiency of phosphorus will not exceed that of the other 
fertilizer elements. 1 f such a condition should develop, any differenti- 
ation in the relation of the ingredients of a fertilizer would then be 
etcrmincd onl\ b\ differences in the growth response of individual 
crops. 

The farmer has held the idea from the time when fertilizers first 
appeared that a given crop should receive a fertilizer especially adapted 
to it. Whatever may be our ideas concerning the scientific reasoning. 
<>\ the fanner, we do well to appreciate his power of observation. He 

had only to watch the growth of the plants to satisfy himself that they 

did not all respond alike to the different materials which he added to 
the land. 

The fertilizer manufacturer was not slow to see the economic ad- 
vantage of complying with this demand. There arose a great variety 
of brands purporting to be for different crops, and the requests of the 



HARTWELL \ CROP RESPONSE TO FERTILIZERS. 



355 



farmers we ife thus fulfilled. To be sure, many of these mixtures for 
special croj$ came from the same pile ; and, likewise, there was a gen- 
erous variety of analyses in brands recommended for the same crop. 

In estimating the fertilizer needs of different crops the manufacturer 
lias taken advantage of such information as was readily accessible, but 
sufficiently definite knowledge has not been available to enable him to 
proceed with any considerable degree of intelligence. 

When fertilizers are inexpensive, or their cost is a minor considera- 
tion, as in the case of the market gardener to whom the rapidity of 
growth of his crops and the labor expense are of more vital importance 
than the cost of fertilizer, there is no hesitation about using more fer- 
tilizer than is actually needed. Used under such conditions, there 
could be quite a wide divergence in the analyses of fertilizers without 
any noticeable differences in the growth of the crop, and there would- 
be no necessity for very careful adaptation of analyses to crops. In 
most circumstances, however, the ordinary farmer desires to apply only 
the least possible amount of fertilizer required by the immediate crop, 
and to avoid especially any excesses which are subject to loss. 

There is no doubt that the growth response to fertilizer constituents 
differs widely. One has only to observe, for example, that, under 
identical conditions, carrots are independent of an application of acid 
phosphate, whereas turnips can make practically no growth without it. 

It appears that farm crops must be grouped in accordance with their 
response to each of the fertilizer ingredients before they can be fed 
intelligently. Because this is a difficult and time-consuming task is not 
a good reason for failure to undertake it. A quite inaccurate grouping 
is justifiable in the beginning as a basis for modification and correction. 

Such attempt as will be made in the present paper to divide some of 
the crops into three groups based on their relative growth response to 
individual applications of nitrate of soda, acid phosphate, and muriate 
or sulfate of potash may be justified only as an incentive to further 
work along this line. 

At the Rhode Island station it has been rather customary to grow a 
number of different kinds of crops for one year crosswise of plats 
designed primarily to determine the effect of different applications to* 
the soil, and in the following year to grow them lengthwise of the same- 
plats. This has given information not only of the different response 
exhibited by the crops, but also concerning the effect of the plants, 
grown one year on those planted the following season. After the two 
years it was, of course, necessary to devote two or three seasons to 
uniform cropping and thoro tilling in an attempt to make the soil suffi- 
ciently homogeneous so that the process might be repeated. 



356 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

By adopting as standards for comparison certain crops to be in- 
cluded each year when a number of others are grown, interpolations of 
the different crops may be made in accordance with the indications 
furnished by the results obtained from time to time. 

The relative growth response to a constituent of a fertilizer has 
usually been measured by a percentage comparison of the crop weights 
obtained with an optimum fertilizer to those obtained where a given 
fertilizer constituent has been omitted. Different combinations of 
nitrate of soda, acid phosphate, and sulfate or muriate of potash have 
been used most generally for this purpose, as in the ordinary so-called 
field soil test. 

It should be recognized clearly that these constituents may have 
effects other than those attributable to their nutritive values, but they 
are, nevertheless, prominent constituents of fertilizers, and it is desired, 
therefore, to know their influence on the growth of different crops. 
It is understood, however, that in experiments of this kind an attempt 
is made to confine the effects of the constituents to the nutrients, nitro- 
gen, phosphorus, and potassium. All other nutrients must be sup- 
plied in optimal amounts in the basal fertilizer which is common to all 
the plats. In brief, every other controllable factor must be made as 
nearly optimum as possible for the several kinds of plants in the 
comparison. 

In an} - one year, even in the same locality, the weather conditions 
will be more favorable to some of the crops than to others, but in a 
of years the advantages may be fairly evenly distributed. It is 
to be expected, even aside from the influence of the soil, that the re- 
sults obtained in one locality may differ from those secured in another. 
Should this be the case, it would only show that, independent of the 
soil, a mixtiirc suited to a crop in one locality might need modification 
for the same crop when grown in another locality. 

I- rc(|iicntlv there are economic reasons for growing a certain crop 
for which soil and climatic conditions are somewhat unsuitable, and 
where necessarily the response to fertilization would be less than in 
more favorable localities. Nevertheless, the response of the crop to 
fert ili/at ion under those same climatic conditions is what the farmer 
desires to know. 

Thai crop which is increased most by the use of a fertilizer chemical 
is the one whi< li may be said to have the highest needs for the fertilizer 
nutrient which the chemical contains. This may be the maximum in- 
rea e either because the particular crop is a poor forager when the 
fertilizer ingredient is absent, a prolific yielder when it is applied, or 



HARTWELL ! CROP RESPONSE TO FERTILIZERS. 



357 



for both reasons. Conversely the minimum increase would result with 
that crop which is the best forager, but the smallest yielder even as a 
result of the addition of a fertilizer ingredient. 
Crops might be classified as follows : 

A. Good foragers, and small yielders even when fed ; 

B. Good foragers, and large yielders when fed; 

C. Poor foragers, and small yielders when fed ; and 

D. Poor foragers, and large yielders when fed. 

Class A would be quite independent of fertilizers, classes B and C 
intermediate in this respect, and class D would return the largest 
increase from the use of fertilizers. 

For any fertilizer constituent groups I, 2, and 3, respectively, may 
be adopted to comprise crops showing low, medium, and high response 
to its application. In the accompanying table a tentative attempt has 
been made to thus grade twenty-one crops, more as an illustration of a 
system for finally arriving at the fertilizer analyses adapted to different 
crops than with the expectation that the grading will prove to be accu- 
rate when subjected to further investigation. The present data for 
the different ingredients decrease in value in the following order : 
Phosphorus, potassium, nitrogen. The writer hopes it will be kept 
distinctly in mind that in certain cases there are scarcely any experi- 
mental data in existence suitable for the purpose under discussion. 
However, our conservatism has been overcome by the hope that inves- 
tigators will be stimulated to secure information that is more reliable. 

In Table 1 the crops are arranged in three groups in an increasing 
series according to their response to the application of, first, nitrogen; 
second, phosphorus ; and third, potassium, the order in which these 
elements are arranged in the designation of a northern fertilizer. Tur- 
nips, for example, are placed in Group 2, or the medium group in 
relation to certain other crops, so far as their relative response to 
nitrogen is concerned ; in Group 3 because of their high response to 
phosphorus ; and in Group 1 with those crops which exhibit low re- 
sponse to potassium. Based upon this grouping, the response relation 
of turnips for the respective nutrients may be expressed as 2 : 3 : 1. 

Now, it is obvious that this relation may differ materially from that 
expressing the relative amounts required, in order that the average 
crop needs for each ingredient may be supplied within economical 
limits. This relation will, of course, differ with the soil, and with the 
cost of the fertilizer ingredients. We will accept the suggestion made 
previously in this paper that for purposes of illustration 2:3:2 be 
adopted for this relation. 



358 



JOURNAL OF THE* AMERICAN SOCIETY OF AGRONOMY. 



Table i. — Tentative arrangement of twenty-one crops into three groups in 
accordance with their increasing response to fertiliser elements. 



Group. 


Increasing 
nitrogen 
response. 


Increasing 
phosphorus 
response. 


Increasing 
potassium 
response. 


Relation of 
ammonia, available 

phosphoric acid, 
and soluble potash 

in fertilizer 
adapted to crop in 
preceding column. 


i 


Rye 

Bean 

Corn 

Cucumber 
Cabbage 
Pea 
Potato 


Carrot 

Buckwheat 

Millet 

Oat 

Pea 

Bean 

Tomato 


Corn 
Rye 

Cabbage 

Turnip 

Bean 

Oat 

Pea 


2 : 6 : 2 (3 : 9:3) 
2 : 6 : 2 (3 : 9:3) 
2 : 9 : 2 (3 : 12 : 3) 
4:9:2 

2 : 6 : 2 (3 : 9 : 3) 
A : 6 • 2 (6 : • 1) 
2 : 6 : 2 (3 : 9 53) 


2 


Wheat 

Sunflower 

Turnip 

Tomato 

Beet 

Carrot 

Oat 


Corn 

Potato 

Rve 

Wheat 

Sunflower 

Barley 

Lettuce 


Millet 

Wheat 

Buckwheat 

Carrot 

Potato 

Tomato 

Barley 


6:6:4 
4:6:4 
6:6:4 
4:6:4 

2 : 6 : 4 (3 : 9 : 6) 

4:6:4 

6:6:4 


3 


Millet 

Parsnip 

Buckwheat 

Lettuce 

Barley 

Squash 

( )nion 


Cabbage 
Beet 

Cucumber 

Onion 

Parsnip 

Squash 

Turnip 


Squash 

Sunflower 

Beet 

Onion 

Parsnip 

Lettuce 

Cucumber 


6 : 9 : 6 (4 : 6 : 4) 

4:6:6 

4:9:6 

6 : 9 : 6 (4 : 6 : 4) 
6 : 9 : 6 (4 : 6 : 4) 
6:6:6 
2:9:6 



For any crop, therefore, which exhibits medium response to the 
application of each of the three fertilizer elements, namely, which is 
in the second group m eacn t*ase, the 2:3:2 relation would be appro- 
priate. According to the table wheat is such a crop; and to derive a 
fertilizer analysis for wheal each figure of the relation may be simply 
multiplied by the group number, 2, with the result that 4:6:4 is the 
wheat fertilizer. 

I de ide on a fertilizer for a crop which does not in all cases give 
this medium response, as, for example, the turnip crop which, as was 
'an d. is in groups 2, 3, and [, respectively, the average relation 2: 3:2 
would be modified 03 multiplying each figure by the respective group 
number in which turnips are placed; that is, 2X2, 3X3. and 2X 

would result in a }:«;:2 fertilizer for turnips. 

B thi method the fertilizer analysis for each of the twenty-one 

in the table ha been derived. In the case of phosphorus, 2 was 
lie multiplier for both groups 1 and 2, because the relation for 

element would be quite unusual to our conception if the smallest 



hartwell: crop response to fertilizers. 359 

factor were used. Even with this exception it happens that ten dif- 
ferent brands were required for the twenty-one crops. 

With our present inadequate knowledge there is no justification for 
so many brands, and it remains to be seen whether further research 
will ever increase our knowledge to the point where such detailed 
attention to analyses for different crops will be reasonable. 

This will depend to a considerable degree upon the relation of the 
cost of fertilizer to the profits of production. The abnormal war 
prices of potassium, for example, stimulated a keener inquiry of the 
necessities of different crops for this element than had ever been mani- 
fested previously. 

If further investigation leads to an accurate grouping of agricultural 
crops in accordance with their relative response to each of the fertilizer 
nutrients, it seems not too much to expect that a correlation will be 
found between the metabolic changes accompanying the formation of 
the proximate constituents of plants and the plant- food ingredients 
which are in some way necessary to those changes. 



AGRONOMIC AFFAIRS. 



MINUTES OF THE ANNUAL MEETING. 

Following are the minutes of the fourteenth annual meeting of the American 
Society of Agronomy, held at New Orleans, La., November 7 and 8. 1921. 

Morning Session, Monday, November 7th, 1921. 

The session was called to order at 9 '.30 a. m. by President Chas. A. Mooers, 
agronomist and vice-director of the Tennessee Agricultural Experiment Sta- 
tion, in Room H, Association of Commerce Building. Forty-two members were 
present. The session was devoted to a symposium on nitrogen in its relation 
to soils and crops and was under the direction of Dr. J. G. Lipman of the 
New Jersey Agricultural Experiment .Station. The following papers were pre- 
sented : 

The Formation and Movement of Nitrates, Dr. J. A. Bizzell, Cornell Univer- 
sity. Ithaca, N. Y. 

Nitrogen Gains and Losses, Dr. F. E. Bear, Ohio State University, Columbus, 
Ohio. 

Types of Farming, Prof. C. G. Williams, Ohio Agricultural Experiment Sta- 
tion, Wooster, Ohio. 

Lime and Other Amendments. Dr. W. H. Maclntire, Tennessee Agricultural 
Experiment Station, Knoxville, Tenn. 

Agricultural and Commercial Values of Nitrogenous Plant Foods, Prof. 
A. W. Blair, New Jersey Agricultural Experiment Station. New Brunswick, 
N. J. (Read by the Secretary.) 



360 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



President Mooers announced the following committees : Resolutions Com- 
mittee, Prof. L. E. Call. Prof. S. B. Haskell ; Auditing Committee, Dr. J. 
R. Fain, Dr. George F. Freeman. 

Afternoon Session, Monday, November 7th, 1921. 

Meeting was called to order by President Mooers at 2:00 p. m. There was 
an attendance of forty-four. 

The following papers were presented, completing the symposium on nitrogen . 

A Glance at the Present and Future Supply of Fertilizer Nitrogen, Director 
S. B. Haskell, Massachusetts Agricultural Experiment Station, Amherst, Mass. 

Green Manures, Prof. M. J. Funchess, Alabama Agricultural Experiment 
Station. Auburn, Ala. 

The Salt Requirements of Agricultural Plants. Dr. A. G. McCall, Maryland 
Agricultural Experiment Station, College Park, Md. 

The annual business meeting was then held. The minutes of the last annual 
meeting were read and approved. The Secretary's report and the Treasurer's 
report were read by the Secretary-Treasurer and accepted. These reports 
follow : 

REPORT OF THE SECRETARY. 

I beg to submit herewith the Secretary's report. 

Since taking over the duties of Secretary of the Society I have been at- 
tempting, first of all, to collect as many of the outstanding dues as possible 
and also to increase the membership of the Society. In the former effort, I 
have been materially aided by Mr. Warburton, our editor, and by our com- 
bined efforts we have succeeded in collecting many of the outstanding dues 
and subscriptions and have reinstated a large proportion of lapsed members. 
On January 1, there were 76 lapsed members. Of these, 28 have been rein- 
stated and 12 have resigned. Of the unpaid subscriptions only 10 have not 
been settled for. 

In the effort to increase the membership I asked assistance from various 
members of the Society located at our agricultural institutions and I have 
■ I i1k most cordial support in every case. I wish to note particularly 
the aid given in increasing the membership of the Society by Prof. J. H. 
Parker of Kansas. Dr. J. O. Morgan of Texas, Prof. A. B. Beaumont of 
M ichusetts, Prof. F. D. Gardner of Pennsylvania, and Mr. G. W. Musgrave 
of New Jersey. Many others have aided by sending in one or more new 
mcmli'Ts. If it were possible for a representative in each state to be chosen 
(mid lecttre as large a number of new members as Professor Parker has 
in Kariiai, we COtlld easily double the membership of our Society. Kansas has 
firfl in membership and I hope during the coming year that we will 
'•• ai.l. to increase, to a lar^c extent, onr membership in other States. 

\\Y have received 1 2 lie* members into the Society and 24 new subscrip- 
tion*. k'ivinK n* at the present time, a total membership of 666 and a total 

subscription list of 141. 

I t mi. there an still 74 members who have not paid their 

1001 dues ami 4.} subscriptions unpaid. Three notices have been sent to the 
I'mili- i effort will be made before the first of the year so that 

nutj be dropped from membership, The lubscriptioni will undoubtedly 

largel) '»< p. ml Many of them come thru agencies and are paid later. 



AGRONOMIC 



AFFAIRS. 



The winter meeting of the Society held in Chicago was a success in every 
way ; a most interesting program was given. Since that meeting the Executive 
Council has voted for affiliation with the A. A. A. S., which has been accom- 
plished, and it is hoped that we may arrange as successful a winter meeting 
at Toronto this winter. Your Secretary was appointed ad interim representa- 
tive of the Society on the Council of the A. A. A. S. and an appointment 
should be made to this position at this meeting. 

Announcements of this meeting at New Orleans were sent to the entire mem- 
bership on return post cards and we have received somewhat over 300 cards 
in reply, 263 replying that they could not attend and cards from 39 announcing 
that they expected to attend. 

Comments have been offered regarding our place of meeting in correspon- 
dence which your Secretary has had with individual members and it has been 
suggested that some centrally located place would permit a larger attendance 
of members. The suggestion has been offered that a meeting be held during 
the summer when experimental work in agronomy may be inspected. Director 
Haskell has suggested the holding of fertility schools at various institutions, 
a very fine suggestion which will be taken up later under new business. Your 
Secretary would urge that some definite action be taken regarding the place 
of meeting of the Agronomy Society for next year. 

A nominating committee for officers was appointed by your President and 
ballots have been sent out from the Secretary's office and a large number 
returned. They are here to be counted by the committee and report made to 
you of the election of officers. The Executive Committee decided to sound 
out the membership of the Society regarding the desirability of increasing the 
dues and the ballot for officers included a second ballot which called for a 
vote on increasing the dues to $5.00 with the idea of enlarging and improving 
the Journal. This ballot will also be counted by the committee. In this re- 
spect your Secretary would like to suggest that in his judgment the Journal 
may be considerably increased in size if advertising were permitted in it and 
he sees no reason why a rather considerable amount of advertising material 
could not be secured. He would urge consideration of this in connection with 
the matter of increasing the dues of the Society. There is no question but 
that the Journal of the Society is its advertisement and while we have been 
doing as well as we could with the amount of money available from dues and 
subscriptions, we could increase the membership of the Society and also in- 
crease the income by having a larger and better Journal. It would seem de- 
sirable to make the editor chairman of a special committee to consider ways 
and means of increasing our income from the Journal and of enlarging and 
improving the same and your Secretary would urge the creation of such a 
committee, this committee to consider the advisability of including advertising 
material. 

Your editor has written that he is unable to file his report at this time but 
has requested that he be permitted to publish his report in the Journal. This 
request should, of course, be granted. It is intended to publish also the Pres- 
ident's address and certain of the papers presented at this meeting, if not all. 
Publication will also be made of the abstracts of papers presented here in 
Science, and your Secretary would urge that abstracts of all papers be placed 
in his hands before this meeting adjourns. 



362 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



In conclusion, your Secretary would ask that any of you who have sugges- 
tions to offer regarding increases in membership, report the same to him and 
any who are willing to secure members for the Society will be supplied with 
necessary blanks and other materials. We would urge, in this connection, the 
desirability of the establishment of local sections at different institutions, as 
several of these are now in operation and proving highly successful. This 
is one of the best means of increasing our membership and of getting our 
students and younger faculty members in touch with the Society. If we do 
not have a committee on local sections your Secretary would urge the appoint- 
ment of a committee at this time. 

Thanking all members of the Society who have so cordially supported our 
office during the past year in all the duties of the office, this report is 
respectfully submitted. 

P. E. Brown, Secretary. 

REPORT OF THE TREASURER. 

I beg leave to present herewith, the report of the Treasurer for the year, 
November. 1920, to November, 1921. 

Receipts. 



Balance from Secretary Carrier $ 200.08 

Dues 1920 and previous years 118.50 

Dues 1921 1,222.95 

Dues, new members. 1921 446.50 

Back numbers of the Journal sold 264.27 

Reprints sold • • 120.14 

Subscriptions 1920 and preceding year 325-04 

Subscriptions, new, 1921 60.05 



Total receipts - - $2,757-53 

1 )l SHURSEMENTS. 

< osl of printing JOURNAL, New Era Printing Co., and Maurice-Joyce 

Engraving Co $1719.91 

Miscellaneous expenses (stationery, stamps, printing, exchange, and 

telegrams) 15448 



TotSl expenses $1,874.39 

Balance on hand .....$ 883.14 

Respect f iilly submitted, 



P, E, BROWN, Treasurer. 

M I S( I I I. A.N I (MS REPORTS. 

( \V War Kur t' .11. brin^ unable to attend, did not submit his editor's report 
but it wav under trior] that he would publish it in the Journal of the Society. 
!>r C V. Piper reported for the Committee on Terminology with an oral 
ri promising to submit a written report at a later date. 



AGRONOMIC AFFAIRS. 



363 



Dr. R. A. Oakley made no report for the Committee on Varietal Standard- 
ization. 

Prof. L. E. Call made an oral report for the Committee on Teaching 
Agronomy, calling attention to the fact that the symposium on teaching crops 
and soils courses prepared as a part of the program of the annual meeting 
really constituted the report of the Committee. 

REPORT OF COMMITTEE OX COOPERATION WITH NATIONAL RESEARCH COUNCIL. 

Dr. C. V. Piper reported for the Committee on Cooperation with the Na- 
tional Research Council. This report was also made orally and a written 
report was to be filed later. The Committee recommended that the fertilizer 
committee of the National Research Council and the committee on salt require- 
ments of agricultural plants be sponsored by the American Society of Agron- 
omy, that the projects outlined by these committees be taken over by the So- 
ciety, and that further projects be developed by the Committee on Cooperation 
and put into operation upon receiving the approval of the Executive Committee. 

Dr. Piper reported three projects: 

1. To assist in publishing the Journal. 

2. Better cooperation among agronomy workers, with an appropriation of $10,000. 

3. Pasture project. 

The first two are paper projects as yet. 

The projects of the fertilizer committee include the preparation of mono- 
graphs on lime and on the genesis of soils and the establishment of a soils 
research institute, all of which are paper projects, and the work on salt require- 
ment of agricultural plants which has been carried on to some extent under 
the direction of a special committee. 

report of committee ox topographic surveys. 

The committee report on topographic surveys prepared by Dr. E. O. Fippin 
was read by the Secretary and adopted. The report follows: 

The agronomists of the United States recognize the fundamental need of 
maps of the States which shall not only represent the geography of the 
country, but also present its physical features in a manner that will serve 
as a guide to and a base for the development and practical use of the resources 
of the. country. 

They recognize in the topographic maps that have already been prepared of 
extensive sections of the country by the Federal Government with some finan- 
cial assistance from the different States, the best type of general maps for 
presenting the geography and relief features of the country, for the representa- 
tion of scientific data depends on geographic and relief features. 

In addition to their general interest in the extension of maps of this type 
over the entire territory of the States, the agronomists of the country are 
particularly concerned to have maps of this type as the base for the survey 
and representation of the soils of the country, in order to make known the 
soil and agricultural conditions and to facilitate the development of the land 
resources. 

Therefore, the members of the American Society of Agronomy assembled 
in convention in New Orleans, this 7th day of November, 1921, endorse the 



364 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



policy of pushing to the earliest practicable completion the topographic survey 
of the United States, thru the cooperation of Federal and State funds to 
that end. along the lines of House Bill 5230 and they urge upon Congress and 
the several States concerted support of measures like the topographic survey 
and the soil survey as basic investigations leading to the development of the 
resources of the country to the benefit of all its people. 

A. R. Whitson, 

B. W. Kilgore, 

E. O. Fippin, Chairman. 

REPORT OF AUDITING COMMITTEE. 

The Auditing Committee submitted their' report which was accepted and 
approved : 

Your Auditing Committee beg leave to state that they have examined the 
books, checks and vouchers of the Treasurer and find the same to be correct. 

J. R. Fain, , 
Geo. E. Freeman, 

Committee. 

report of nominating committee. 

The Nominating Committee, consisting of Dr. C. R. Ball and Dr. C. V. 

Piper, reported that ballots for officers of the Society had been sent to the 

entire membership and 321 ballots were returned to the Secretary. These 
ballots had been counted with the following results : 

President, Dr. T. L. Lyon, 301. 
First Vice-President, D. E. Stephens, 306. 
Second Vice-President, A. B. Conner, 304. 
Secretary-'} 'rensurer , P. E. Brown, 320. 

A letter from Dr. Lyon stated that he could not accept if elected and the 
Nominating Committee then placed the name of Prof. L. E. Call in nomina- 
tion for President. Upon motion which was duly seconded and carried, 
Professor Call was unanimously elected president of the Society for the en- 
luing year. On being called upon, Professor Call responded in a timely talk 
upon all ni< iii!,< r- the desirability of aiding in the work of the Society* 
lUppOrting it in all its activities, and especially asking aid in increasing the 
membership. 

miiuation WITH ASSOCIATION FOR ADVANCEMENT 01 SCIENCE. 

('•■ idcnl Moocr* reported the Society as having affiliated with the Amcr- 
n for the Advancement of Science and that upon the basis of 
numlx-r of Fellows in the Association who were members of the Society, it 
entitled to One representative on the Council. The Secretary had been 
tiiiK as ad interim representative. 

Upon motion irbirli seconded and carried, Prof. C. A. Mooers was 

elected representative on the Council of the A. A. A. S. 



AGRONOMIC AFFAIRS. 



365 



COOPERATION WITH NATIONAL RESEARCH COUNCIL. 

Dr. C. F. Marbut of the Bureau of Soils was then elected by unanimous 
ballot to the committee on cooperation with the National Research Council 
for a five-year term, filling the vacancy left by the completion of Professor 
Call's term. 

AMENDMENTS TO CONSTITUTION. 

Director S. B. Haskell presented the following amendments to the Consti- 
tution of the Society which could not be voted on as notification had not 
been sent to the membership. It was understood that these amendments would 
be held over until the next annual meeting for definite action. 

To replace Articles VI and VII of the present constitution by the following : 

Article VI. The officers shall consist of a president, an executive committee 
of five, and a secretary-treasurer. The president and secretary-treasurer shall 
be members ex officio of the executive committee. 

Article VII. The duties of these officers shall be those usually pertaining 
to their respective offices. The terms of office shall be as follows : 
President, one year. 

Executive committee, five year's, with one member retiring annually. 
Secretary-treasurer, one year, or until his successor is appointed. 

The president and members of the executive committee shall be elected by 
ballot. The secretary-treasurer shall be appointed by the executive committee. 

ANNUAL DUES. 

The Secretary reported results secured on the ballot submitted to the mem- 
bership of the Society regarding increase in dues. Three hundred and twenty 
ballots were returned with the following results : 

Opposed to increasing the dues to $5.00, 175. 

In favor of increasing the dues to $5.00, 145. 

Number who will resign if the dues are raised. 42. 

Number who will not resign if the dues are raised. 232. 
The discussion of this report was then entered upon and the motion was 
made that the dues be increased to S4.00. This motion was lost, it being con- 
sidered that the majority of the Society, according to the ballots, were op- 
posed to any increase in dues. 

OTHER BUSINESS. 

The matter of advertising in the Journal was left to the executive com- 
mittee with power to act. 

A discussion of meetings, annual and special, and the holding of fertility 
schools was taken up. These matters were also referred to the executive 
committee. 

President Mooers presented the proposition of the Agronomy Section of the 
Southern Agricultural Workers to affiliate with the Society. As no provisions 
of the Constitution provide for such affiliation, it was moved and carried that 
the matter be referred to the executive committee with the suggestion that the 
Constitution be amended to provide for such affiliation. 



366 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



The recommendation of the Committee on Cooperation with the National 
Research Council was presented by Dr. Piper and it was moved and carried 
that the committee on cooperation be given power to assimilate the various 
agronomy projects of the Council and bring them under the jurisdiction of 
the American Society of Agronomy. 

The recommendation was also approved that the committee on cooperation 
prepare and put into operation such other projects as they might see fit, se- 
curing the approval of the executive committee. 

Evening Session, November 7, 1921. 

The evening session was a joint meeting of the American Society of Agron- 
omy and the Society for the Promotion of Agricultural Science. A joint 
dinner was held at the Louisiane Cafe, arrangements having been made by 
Prof. A. F. Kidder. Following the dinner the meeting was called to order 
by Dr. C. R. Ball and the annual addresses of the retiring presidents were 
given as follows: 

The Agronomic Placement of Varieties, Prof. C. A. Mooers, Agricultural 
Experiment Station, Knoxville, Tenn., President of the American Society of 
Agronomy. 

The Relative Growth Response of Crops to Each Fertilizer Ingredient, Dr. 
Burt L. Hartwell. Agricultural Experiment Station, Kingston, R. I., President 
of the Society for the Promotion of Agricultural Science. 

A third paper was then presented by Dr. E. B. Forbes entitled, The Mineral 
Metabolism of the Milch Cow. 

About 50 were present. 

Morning Skssion, Tuesday, November 8, 1921. 

This session was called to order at 9 :oo a. m. by President Mooers and the 
program consisting of a symposium on teaching crops and soils courses was 
presented under the direction of Prof. L. E. Call of Manhattan, Kan. The 
following papers were presented : 

Some of the Teaching Problems of the Southern Agronomist, Dr. J. R. 
Fain. Georgia State College, Athens, Ga. 

PfOgreSfl in Standardizing the Elementary Courses in Soils, Prof. M. F. 
Miller, University of Missouri, Columbia, Mo. 

\ I'lea i'<»r Experimental Work <>n Methods in Crops and Soils Teaching, 

* • tor S I'.. Haskell, Massachusetts Agricultural College, Amherst. Mass. 

What Should Constitute the Recitation Work of a Five-Hour Course in 
Elementary Farm Oops, Dr. YV. ('. Ethcridge, University of Missouri, Co- 
lumbia, Mo. 

In addition t<> these papers. I'mf. L. E. Call reported briefly on the con- 
ference of crops teachers at Urbana. 

Df W. K Heiulrix spoke briefly f<>r the committee on laboratory work in 
farm CTOpi and Prof, S. C. Salmon outlined the work of the committee on 

intercollegiate grain judging contests. 

\ discussion of th( papei was led by Prof L E, Call with a number of 

member! participating, The discussion (entered very largely about the report 
by l)r Ethcridge "ii a five hour course in elementary farm crops. A copy of 



AGRONOMIC AFFAIRS. 



this report is submitted separately. (To be printed with other papers presented 
at this session. Ed.) 

The matter of a National Students' organization in agronomy was pre- 
sented by Dr. Etheridge and it was moved and carried that a committee of 
three be appointed to plan for a national organization. 

Afternoon Session, Tuesday, November 8, 1921. 

This session was called to order by President-elect Call at 2 :oo p. m. The 
following papers were presented : 

The Terminology of the Subdivisions of Agriculture and Some of the 
Broader Factors Relating to Plant Production, Dr. C. V. Piper, U. S. Dept. 
of Agriculture, Washington, D. C. 

The Influence of Fertilizers on the Yield and Maturity of Soy Beans, Prof. 
Geo. L. Schuster, Delaware Agricultural Experiment Station, Newark, Del. 

A New Muck Soil Problem and Its Solution, Prof. M. E. Sherwin, North 
Carolina State College, West Raleigh, N. C. 

Soil Types as a Basis for Soil Investigations, Dr. P. E. Brown, Iowa Agri- 
cultural Experiment Station, Ames, Iowa. 

Potassium-Nitrogen Ratio of Red Clover as Influenced by Potassic Ferti- 
lizers. Dr. Paul Emerson, Iowa Agricultural Experiment Station, Ames, Iowa 
(read by the Secretary). 

In addition to these papers Prof. J. C. Pridmore presented the report from 
Prof. L. E. Rast on the Control of Cotton Diseases by the Use of Potash 
Fertilizers. 

Prof. S. C. Salmon reported for' Prof. Wiancko on the Standardization of 
Field Experiments and it was moved and carried that this committee be re- 
tained with the addition of two new members and a further report be made 
at the next annual meeting. The report of this committee is filed separately. 

Prof. C. F. Marbut's paper on Our Inventory of Soil Nitrogen was pre- 
sented by the Secretary. 

Prof. S. C. Salmon reported for the committee on Intercollegiate Grain 
Judging Contests and in accordance with the motion which was duly carried, 
this report will be multigraphed and sent to instructors in all agricultural in- 
stitutions and the committee will be continued with power to take such action 
as they may see fit in regard to the holding of contests next year. 

Prof. L. E. Call then reported for the committee on resolutions as follows: 
Resolved: That the American Society of Agronomy extends to all of those 
who assisted in making its 1921 meeting a success its heartiest thanks. 
Particularly does it appreciate the service of its retiring president, Dr. 
Mooers, who in a most able and efficient way has handled the business 
of the Society during the year just passing; of Dr. Brown, its Secretary, 
for the energy, ability and enthusiasm which he has put into the work; 
and of Dr. Lipman and Prof. Call, chairmen of the Symposium Com- 
mittees, for the great care and thought given to the development of a 
program of outstanding value. 
Resolved: That the Society extend to Mr. Warburton, retiring Editor, sincere 
thanks and appreciation for the services rendered so efficiently and untir- 
ingly in the past; and to Dr. Thatcher, Editor-elect, for his willingness 
to undertake the onerous duties of this important position. 



308 JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 

Resolved: That the thanks of the Society be extended to the New Orleans 
Association of Commerce for the courtesy extended in allowing to the 
Society use of the assembly room. 

Resolved: That the thanks of the Society be extended to Prof. A. F. Kidder 
for his aid in arranging for this meeting of the Society. 

Resolved: That the Society go on record as favoring an active campaign for 
the establishment of group sections of the Society, in each of the more 
important soil and crop areas of the country. 

Resolved: That the Society urge upon the officers of these group sections the 
desirability, and likewise the necessity, of so conducting the work of the 
section as to enable all persons interested to participate, men in Govern- 
ment service, in College, Extension, and Experiment Station Service, and 
in Count}' service. It suggests that the columns of the Journal of 
Agronomy be used freely with this end in view. 
This report was unanimously accepted. 
The meeting adjourned. 

P. E. Brown, Secretary. 

REPORT OF COMMITTEE ON STANDARDIZATION OF FIELD 

EXPERIMENTS. 

The question of standardizing methods of conducting field experiments has 
been carefully studied by this Committee for several years. Information con- 
cerning the practices of the majority of the experiment station workers in 
this country has been collected. Wherever experiments in methods have 
been conducted the results have been analyzed. With the data at hand, the 
Committee now feels that the Society should make a start towards defining 
and adopting certain standards for locating, laying out and conducting the 
ordinary kinds of field experiments. In certain features of field experimental 
w rk there can be no question of the desirability of all workers adopting the 
same methods of procedure, in other features there are doubtless good 
variaii'»n. and considerable latitude must be allowed. The great 
variety of conditions under which field experimental work must be done 
makes it impossible, in certain respects, to lay down anything but very gen- 
eral rules. Nevertheless, certain guiding principles can be set clown for 
making Mich work more uniform and the results more accurate. 

It i- not the expectation of the Committee that the adoption of certain 
Standard! at this time should preclude further investigations in methods or 
hinder progress in the development of better methods. It should rather 
Itimulate further study. Whatever standards may be adopted, it should be 

• - <<\ that they arc open to revision. The following recommendations 
00 tilling Standards are offered for consideration and the Committee would 

• that they he published in the Journal and studied by the members 

f'»r a year before taking final action on their adoption. 

Recommim'Id Standards for Field Plat Experiments in Soil Fertility. 

Location of /ixftfriments.—SnW fertility experiments should be located with 
'Mi' ]"<ati"ii should he representative of the type 



AGRONOMIC AFFAIRS. 



369 



of soil to which the results of the experiments are to be applied. Only one 
type of soil should be represented in any one experiment. 

Uniformity of Soil. — The uniformity of any piece of land for experimental 
purposes should be ascertained before beginning experiments. If the history 
of the land as to system of cropping and soil treatment for several years 
back is not known, it should be tested by a uniform system of cropping with- 
out soil treatment thru one or more years until its suitability for the pur- 
pose is established. Before soil treatment experiments are begun, representa- 
tive samples of the soil and subsoil should be carefully taken for such 
analyses as it may be desired to have for future reference. 

Topography. — For all ordinary field experiments, the land should be reason- 
ably level and slope in one direction only ; otherwise, special precautions must 
be taken to prevent soil washing. Each plat should be graded and slightly 
crowned in the middle to avoid depressions where water might stand or 
ice might form. This can be accomplished by plowing each plat by itself 
with the back furrow in the middle of the plat. Land subject to erosion 
must be only very slightly crowned. This grading or crowning of the plats 
should be done before any special soil treatments are applied. 

Drainage. — When artificial drainage is required, the drains should be lo- 
cated so as to influence all plats alike. Where irrigation is practiced provi- 
sion must be made to water all plats at the same time and at the same rate. 

Size of Plats. — While the size of plats must often be governed by the 
number of plats required for the particular experiment and the amount of 
land available, twentieth-acre to tenth-acre plats will usually be found most 
desirable where horse and machine labor are to be used. There is seldom 
any advantage in larger plats. Xo field of any considerable area is altogether 
uniform. Where a large number of plats is required for the experiment, the 
smaller size will usually be most desirable because of unavoidable soil varia- 
tions between the first and last plats of a large series and the time squired 
for cultural operations. 

Shape of Plats. — Long and narrow plats laid out crosswise of the greatest 
soil variation are preferable to square or short and broad plats because the 
latter are more likely to show important differences in natural fertility. The 
long, narrow plats are also most convenient in conducting cultural operations. 
For example, a plat 14 feet in width can be seeded by one round of a 7-foot 
grain drill and will accommodate four corn rows, and generally something 
near this width should be regarded as a minimum. Extremely narrow plats 
increase the difficulty of keeping fertilizer or manure treatments within the 
plat limits. 

Marking the Plats. — The four corners of any series of plats should be 
marked by permanent markers set below the bottom of the plow furrow as 
a basis from which to measure in case individual plat stakes should be moved 
out of line. Markers for individual plat boundaries should be set in the 
turnways even with the surface of the ground so that implements will pass 
over them. 

Frequency of Check Plats. — Uniformly treated plats thru which to compare 
the different treatments in the experiment should be regularly distributed thru- 
out the series. At least every fourth plat should be such a check. Having 
every third plat a check is preferable since this provides a check plat on 
one side or the other of each differently treated plat in the experiment. 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Treatment of Check Plats. — All check plats should receive a uniform soil 
treatment that will maintain them in a reasonable state of productiveness and 
make possible a normal growth of each crop in the rotation. This will pro- 
vide a uniform standard of comparison thruout the duration ot the experiment. 

Untreated Plats. — One or more plats receiving no soil treatment whatever 
should be included in each series of plats employed in the experiment to show 
how the soil naturally behaves under the particular system of cropping to 
which it is subjected. In large series there should be one such untreated plat 
at each end and one in the middle. 

Replication of Treatments. — The complete series of treatments, including 
check plats, should be repeated as many times as there are crops in the rota- 
tion employed. Thus, with a 4-year rotation there should be four series of 
plats in each of which the entire set of treatments is repeated in the same 
order. This provides for growing every crop in the rotation every year, sub- 
jects every crop to the same seasonal influences, and gives four differently lo- 
cated plats to get a fair average of the effect of each treatment on the par- 
ticular soil type for each crop as well as for the rotation as a whole. When 
the experiment deals with a single crop, the entire series of plats should be 
at least duplicated on the same soil type. In general soil fertility tests, at 
leasl three crops of different classes should be used, as for example a cul 
tivated crop, such as corn, a small grain crop, and a clover or grass crop. 

Interspaces and Borders. — The plats in all soil fertility series should be 
separated by untreated interspaces at least three feet in width. Where corn 
or other cultivated, crops are included in the rotation, the interspace may con- 
veniently consist of one row planted in the middle of the space and removed 
at harvest time. For small grains and hay crops the interspace may be either 
sown the same as the plats and cut out at harvest time or it may be left un- 
lOWed and kept clean by cultivation. There should also be interspaces be- 
tween the outside plats and borders. 

The entire series of plats should be surrounded by regularly planted side 
and end border strips to be cut off at harvest time. Such borders should be 
at least 3 feet wide or equal to one or two hills or rows where cultivated 
crops are included in the rotation. Borders and division strips set with 
permanent grass may be substituted for cultivated borders and division strips, 
and may be advisable where there is danger of soil washing from one plat 
to the next. 

I'nxfnrm Stand <>f I'lants. — Only high quality, acclimated seed of standard 
Witty should be used The seed bed must be uniformly prepared and the 
rate and method of seeding should be such as to secure a uniform, normal 
Stand of plants Mi) nil plats. 1 1 ill-planted crops should be planted thicker than 
aired ind then thinned tO the desired stand soon after the plants are up. It 

often wise to plant extra lulls for transplanting to nil up gaps in the stand. 

! U ■'! Chick I'lats in Making Comparisons Between Differently Treated 
When frequent, uniformly treated and equally distributed check plats 

ar<- employed it is usually most satisfactory to assume that the difference be- 
tween any tw<> check plats is uniformly progressive and calculate a normal 
check yield for each intervening plat as a basis for determining the effect of 
• pafticulai treatment While this method is seldom if ever strictly accurate, 
Usually bettCf than to compare directly with the nearest check plat or with 



AGRONOMIC AFFAIRS. 



371 



either the average of the two nearest checks or the average of all the check plats 
in the series. It is therefore recommended that calculations of increases pro- 
duced by treatments be based on the assumption that the difference between the 
two nearest check plats is uniformly progressive. Thus, if plats 1 and 4 are 
uniformly treated check plats and plat 1 has produced 50 bushels of corn and 
piat 4 has produced 53 bushels, it should be assumed that plat 2 would have 
produced 51 bushels and plat 3 would have produced 52 bushels, if they had 
received the same treatment as plats 1 and 4. Then, if plat 2 actually produced 
56 bushels, the increase credited to the treatment would be 5 bushels and if 
plat 3 actually produced 58 bushels the increase credited to the treatment would 
be 6 bushels. 

Cultural Operations. — All cultural operations except plowing should be con- 
ducted lengthwise of the plats to avoid all possibility of moving soil or fer- 
tilizer materials from one plat to another, except perhaps that hill-planted crops 
may be cross cultivated once or twice to clear out weeds, using implements that 
will not drag the soil. Plowing should usually be crosswise of the plats with 
a double or right and left hand plow, beginning at one end of the plats and 
turning all the furrows one way and leaving no dead-furrow. Where grass 
division strips are used, the plowing should be lengthwise and all plats should 
be plowed on the same day. The direction of turning the furr'ow should be 
alternated at successive plowings. • Any one cultural operation should be per- 
formed with only one implement without change of adjustment and should be 
completed on the same clay. Interruptions in cultural operations may cause 
serious differences in crop development. For this reason, in large series, two 
or" three implements of the same make and similarly adjusted will hasten the 
work and avoid delays otherwise caused by weather conditions. 

Determining Yields. — Yields should usually be determined by harvesting and 
weighing the produce of the entire plat. The produce must be uniformly dried 
before weighing. In case this can not be done, the moisture content should 
be determined and proper corrections made before recording the weights. 

Recommended Standards for Field Experiments with Farm Crops. 

The Seed. — All seeds used for planting shall be of l^nown vitality and free 
from mixture, weed seeds, and contamination or infection by plant diseases, so 
far as this can reasonably be accomplished. 

Except where adaptation of varieties or effects of previous environment is 
an essential part of an experiment, acclimated seed only shall be used. In 
varietal tests of corn, where crossing makes a strict observance of this rule 
impractical, it is recommended tha.t seed be used that has been grown as near 
as possible to the locality where the test is to be conducted. 

Careful efforts to identify unknown varieties introduced into experimental 
work should be made before publication of results and new names should not' 
be applied except in case of necessity. New varieties should be named as soon 
as it is decided to release them for general use. Records of the history of all 
seeds used should be made and kept on file. 

The Soil. — The soil for experimental plats should be as nearly as possible 
of the type prevailing in the area where the data from the crops grown on 
them are to be applied. 



37- JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Where artificial drainage is required, the drains should be located so as to 
influence all the plats alike. Where irrigation is practiced the applications of 
water, must be regulated and made the same for all plats. 

The lay of the land and the general condition of the soil should be as 
uniform as possible. Slopes steep enough to wash materially must be avoided. 
It is important that for several years prior to its use for experimental pur- 
poses the cropping, fertilization, and tillage of the land shall have been 
uniform. 

Good rotations accompanied by ordinary fertilization are necessary in varietal 
and cultural work to keep the productivity of the soil up to normal. 

When a field or series of plats has been occupied by varietal or cultural tests, 
at least one bulk crop should intervene before it is again used for such tests. 

The Plats. — As a rule, relatively long and narrow plats are to be preferred, 
both because of convenience in using machinery and because of greater' ac- 
curacy on uneven land, in which case the plats should be laid out so that all 
will partake alike in the inequalities of the soil. The width of plats should be 
sufficient to allow for the removal of border rows, as hereinafter provided for, 
and to permit the most convenient use of machinery. Plats 5 feet or more in 
width, for small grains and forage crops, and wide enough for four rows of 
intertilled crops, such as corn and potatoes, are generally satisfactory. The 
length of plats may be determined largely by the amount and character of the 
land available. In general, field plats should not be smaller than one-eightieth 
nor larger than one-twentieth of an acre. 

When, for lack of sufficient space, it becomes necessary to locate part of 
the plats in any particular experiment on a different piece of land, the break 
should always be made where a replication of varieties or treatments begins. 

For rotation work and for ascertaining the effect of crops on those which 
follow, it is necessary to establish permanently the boundaries of each plat 
by setting suitable markers. For these purposes, plats should be at least I 
rod wide. 

Check Plats. — Adequate replication of varieties or treatments removes the 
necessity of including check plats. If check plats are included for the purpose 
of deriving probable error's from yields, a large proportion of such plats ap- 
peari to be necessary.! If a check variety is used in varietal tests, it should be 
used on e very third to every fifth plat and it should be a standard, well adapted 
variety. 

Replication of Plots, — The number of years a test is continued, together 
with the number <-f plats devoted to any one variety or treatment and the size 
Of the plats, relate definitely tO the probable error for any particular test. 
When lingle platfl Of varieties or treatments are used, the probable error will 
iverage lower OH t cut h-acrc plats than On plats of smaller size. The increase 
• '.able error on successively smaller plats is relatively small when the 
<d reduction in size of plats is considered. By repeating varieties or 
treatments a sufficient numbei of times on regularly distributed plats <>f any 
size suitable to the purpose of the experiment, the probable error for the 
tc»t ON | luced to Miy poinl considered necessary. For ordinary condi- 

tion!, from two to five replications are recommended. Two plats of ;my 
variety or treatment continued through four years, or three plats continued 
tbre< ear* should be regarded as the minimum. 



AGRONOMIC AFFAIRS. 



373 



Removing Outside Rows. — When varieties are planted adjacent to each 
other, without the intervention of alleys, certain ones may affect others ad- 
versely. When plats are flanked or surrounded by alleys, it is known that 
the yields are increased and that all varieties are not influenced alike. To 
obviate these difficulties, it is recommended that two drill rows from either 
side of each plat in the case of small grain, and an equivalent width in the 
case of broadcasted grains or' forage crops, and one row from either side of 
each plat in intertilled crops, be removed before harvest or left unharvested. 

The Mechanical Operations. — Drills and planters should be carefully cali- 
brated before seeding. A check on the stand should be secured by counting 
plants before tillering takes place. In the case of the larger intertilled crops, 
the seeding should be somewhat thicker than necessary and the stand thinned 
to the desired degree at an early stage of growth. In varietal tests where 
different varieties have different sized seeds, the rate of seeding drilled or 
broadcasted crops should be adjusted so as to get as nearly as possible the 
same stand of plants for all the varieties in the test. With hill planted crops 
such as corn, in which large and small varieties are included in the same test,, 
there may need to be two or three different rates of planting certain varieties 
so as to insure fair comparisons. 

All operations should be uniform for any one experiment. Plowing, seeding, 
or any one cultural operation should be begun and finished on the same day. 

On plats of broadcasted crops and across the ends of plats with drilled 
crops, wires stretched on the ground in the proper places w r hen the crops are. 
quite small facilitate the accurate removal of borders. 

Determining Yields. — When it is impractical to harvest and determine yields-, 
from entire plats, a minimum of six representative rod rows or square yards,, 
or other areas of similar size, uniformly distributed within the plat, avoiding 
borders, may be used. 

Two capable men shall be present at all times when weighings are made, 
with definite instructions that all weights must be checked. 

In determining yields, possible differences in the moisture content of the 
crop should be considered and moisture determinations and proper correc- 
tions made when necessary. This is of special importance in tests with, 
forage crops and in the case of late maturing varieties of corn. 

The results of varietal tests on rich land should not be averaged with: 
those on poor land, but should be used separately with the view of determin- 
ing the adaptability of the varieties to each condition. 

The Publication and Interpretation of Results. — It is recommended that 
sufficient data be published to permit the reader to draw independent conclu- 
sions. 

In technical and semitechnical publications, it is recommended that probable 
error of yields for each season be given. 

Odds of 31 to 1 against a difference in yield between any two varieties or 
treatments being due to normal variation are as low as it seems desirable to 
accept. 

New varieties, cultural methods, or treatments materially different from 
those in common usage shall not be recommended for general use unless sup- 
ported by at least three years of replicated and carefully conducted field experi- 
ments within the area for which the recommendations are made. This shall 



374 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



not be interpreted as sanctioning such recommendations simply because they 
are supported by the minimum of experimental data nor as discouraging the 
early publication of experimental results for the benefit of technical workers. 

Additions to Bibliography. 

The following titles should be added to the bibliography of this subject 
published in the December', 191 7, December, 1918, and December, 1919, issues 
of the Journal of the American Society of Agronomy : 
Arny, A. C. Further experiments in field technic in plot tests. In Jour. Agr. 

Research, 21, no. 7, p. 483-499. 1921. 
Bear, F. E., and McClure, G. M. Sampling soil plats. In Soil Science. 9, 

no. 1, p. 65-75. 1920. 
Day, J. YY. The relation of size, shape, and number of replications of plots 

to probable error in field experiments. In Jour. Amer. Soc. Agron., 12, 

no. 3. p. 100-105. 1920. 
Harris. F. S., and Butt, N. I. The unreliability of short-time experiments. 

In Jour. Amer. Soc. Agron., 12, no. 5. p. 158-167. 1920. 
Harris. J. A. Practical universality of field heterogeneity as a factor in- 
fluencing plat yields. In Jour. Agr. Research, 19, no. 7, p. 279-314. 1920. 
Harris. J. A., and Scofikld, C. S. Permanence of differences in the plats of 

an experimental field. In Jour. Agr. Research, 20, no. 5, p. 335-356. 1920. 
Kikssklrach. T. A. Experimental er'ro'r in field trials. In Jour. Amer. Soc. 

Agron.. 11. no. 6, p. 235-241. 1919. 

LBACH, T. A. Plat competition as a source of error in crop tests. In 

Jour. Amer. Soc. Agron.. 11, no. 6, p. 242-247. 1919. 
?< h m im.wi mi, \\\, MEYER, D., and Mvntkr, F. Parcel size experiments. In 

Arb. Deut. Landw. Gesell., no. 296, p. 51. 1919. Abs. in Expt. Sta. Rec, 

44. j 1 4. 1920. 

SekLIEN, J. Modem methods for experiments with fertilizers and manures. 

In J<>ur. Agr. Sci., 10, no. 4, p. 415-419. 1920. 
STEWART, F. C. Missing hills in potato fields: Their effect upon yield. New 

Y<.rk State Agr. Expt. Sta. Bui. 459, p. 45-69. 1919. 

Respectfully submitted, 

A. T. WlANCKO, 
A. C. Arny. 
S. ('. Salmon, 

Committee. 

REPORT OF THE COMMITTEE ON TERMINOLOGY. 

You: < Otnmtttec begl t<. report that it has made some progress toward com- 
filossarj of AKronomic Terms, tho not as much as had been hoped. 

With th<- progress of the work it becomes more and more evident that many 
w needed, and many such will be proposed, it will be most de- 
sirable to present them first in the Joiknaf, so ;is to secure the benefits of criti- 



AGRONOMIC AFFAIRS. 



375 



cism, and if feasible the plan will be followed. Your Committee hopes that 
it may finish its task in the not remote future. 

Respectfully, 

C. V. Piper. Chairman, 
C. R. Ball. 
H. L. Shaxtz. 

REPORT OF ADVISORY BOARD OF THE AMERICAN SOCIETY 
OF AGRONOMY APPOINTED TO CONDUCT RELATIONS 
WITH THE NATIONAL RESEARCH COUNCIL. 

Your Advisory Board has thus far suDmitted to the Division of Biology and 
Agriculture of the National Research Council only two projects, one asking for 
$1,000 per annum to assist in financing the publication of the Journal of the 
American Society of Agronomy; the other" requesting $10,000 a year for 
bringing about greater efficiency in agronomic investigations through "coordina- 
tion and cooperation. Both projects were approved, but thus far no aid has 
been forthcoming, not thru any fault of the Research Council. 

A third project, dealing with the pasture problem in its broadest aspect, has 
been approved in principle by the Division of Biology and Agriculture, and 
the finished project will soon be presented. This project originated outside 
of your Advisory Board, but as the Division of Biology and Agriculture deemed 
it important it was practically necessary for your Board to formulate the same, 
as it is primarily agronomic. The approval of the Society to this action of 
your Advisory Board is desired. 

There are certain other Research Council projects, agronomic in nature, 
which originated during the war and which have been conducted by special 
committees. The Division of Biology and Agriculture now desires that these 
committees and their projects be sponsored by the American Society of Agron- 
omy, as it desires all projects which are undertaken be backed by the scientific 
society directly concerned. There are two of these committees, as detailed 
below. ' 

Committee on Fertilizers for 1921-22. 

J. G. Lipman, Chairman, B. E. Livingston, 

Agricultural Experiment Station Johns Hopkins University, 

New Brunswick, N. J. Baltimore, Md. 

E. W. Allen, A. G. McCall, 

Department of Agriculture, University of Maryland 

Washington, D. C. College Park. Md. 

F. J. Alway, A. E. Wells, 

University Farm, 60 Broadway, 

St. Paul, Minn. New York, N. Y\ 
Samuel Avery, ' A. B. Lamb (liaison member, Divi- 

University of Nebraska. sion of Chemistry and Chem- 

Lincoln, Nebraska. ical Technology), 

K. F. Kellerman, Harvard University, 

Bureau of Plant Industry, Cambridge, Mass. 
Washington, D. C. 



3/6 



JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



Sub-Committee ox Physiological Salt Requirements of Plants 

FOR 1921-22. 

A. G. McCall, Remainder of membership not ap- 

University of Maryland, pointed yet. 

College Park. Md. 

Committee on Fertilizers for 1920-21. 

T. G. Lipmax. Chairman, William Crocker, 

Agricultural Experiment Station. Thompson Institute for Plant 

New Brunswick, N. J. Research, 
K. F. Kellerman. Yonkers, N. Y. 

Department of Agriculture, B. E. Livingston, 

Washington, D. C. Johns Hopkins University, 

Baltimore, Md. 

The Committee on Fertilizers has several projects before the Research Coun- 
cil, as follows : 

Soil Research Institute J. G. Lipman, Chairman. 

Monograph on Lime W. H. Maclntire, Chairman. 

Monograph of History of Soil Development, C. F. Marbut, Chairman. 

The Sub-Committee on Physiological Salt Requirements of Plants has a 
single major project. 

The present membership of your Advisory Board is as follows: 

Robert Stewart, term of office expires December, 1925. 

C. V. Piper, Chairman, term of office expires December, 1924. 

J. G. Lipman, term of office expires December, 1923. 

J. W. Gilmore, term of office expires December', 1922. 

L. E. Call, term of office expires December, 1921. 

I term of Prof. L. E. Call expires December, 1921, and requires action 
on the part of the Society. 

C. V. Piper, 
Chairman. 



REPORT OF THE EDITOR. 

1 li< volume <>f the Joikxae of Tin-: American Society of Agronomy 

has been 1 1 ( ry satisfactory one so far as contents are concerned, but has 
been unsatisfactory in other ways. Insufficient funds have made necessary a 
" tricted Otttpllt, so thai there lias been a gradual accumulation of unpub- 
L-r- in the hands of the editor, with the result that a long interval 
elapses m practically every ease between the date of submission of a paper 
and its publication. For instance, the papers presented at the special meeting 
of tlx- Sodcty in December, io..'o, have not yet been published, due to the fact 
1 flu icnt other papers were on hand before thai time to fill the available 



AGRONOMIC AFFAIRS. 



377 



space during 1921. Labor troubles in the shop where the Journal is printed 
have caused long delays in issuance of the numbers since April, with attendant 
annoyances. Then, too, the editor has been engaged in work during the greater 
part of the year which has made the handling of copy and the prompt reading 
of proof difficult or practically impossible. 

As to the make-up of the Journal for 1921, it contains 41 papers by 41 
authors, contributed from 21 States, the District of Columbia, and one of the 
Canadian provinces. This is a far wider distribution of source of material 
than has been common and goes to show that the Journal is reaching a wider 
field. Two particularly valuable series of papers resulting from the 1920 
meeting of the Society were printed during the year, one on agronomic teach- 
ing being printed in the February number and one on liming running thru the 
March, April, and May numbers. In addition to the technical papers, the 
Journal has contained three book reviews, reports of seven agronomic meet- 
ings, and nearly a hundred news items. 

A year ago the editor expressed his desire to be relieved from further duty. 
The executive committee of the Society found difficulty in inducing any one 
else to take up the work, so it was continued with the understanding that 
other arrangements would be made as soon as practicable. I am glad to say 
that the executive committee has now arranged to have Dr. R. W. Thatcher, 
who has been closely identified with the Society since its beginning and who 
has been a member of its editorial board for several years, to take up the 
editorship with the beginning of the next volume. The present editor wishes 
to thank the members of the Society, and particularly the editorial board of 
the Journal and those who have contributed to its pages, for their forbear- 
ance and their words of encouragement and helpfulness, and to bespeak for 
the new editor the same courtesy that has been uniformly extended to him. 

It seems fitting to review briefly the accomplishments of the seven years of 
my connection with the Journal of the American Society of Agronomy. 
During that time 53 numbers have been issued, containing a total of 2,488 
pages. The 259 papers which have been printed have been illustrated with 58 
plates and 151 text figures. In addition to the minutes of the annual meeting 
which have been printed each year, brief reports of 45 sectional meetings have 
been printed, as have 7 book reviews and 696 news items. 

Respectfully submitted, 

C. W. Warburton, Editor. 

NOTES AND NEWS. 

E. E. Barker, chief agronomist at the Porto Rico Insular Station, 
has resigned. 

F. L. Duley has been granted a year's leave of absence from the 
Missouri station and will make special studies in soil acidity and 
plant nutrition at the Wisconsin station. 



37$ JOURNAL OF THE AMERICAN SOCIETY OF AGRONOMY. 



J. H. Harlan, assistant in agronomy at the New York State station, 
has been granted a year's leave of absence for graduate work at 
Cornell University. 

R. C. Parker, in charge of the eastern bureau of the National Lime 
Association, has moved his headquarters from Riverhead, N. Y., to 
Springfield. Mass. 

H. J. Webber, who has been associated with the Pedigree Seed 
Farms at Hartsville, S. C, recently, has returned to the California 
station as Professor of Citriculture and Director of the Citrus Ex- 
periment Station at Riverside. 

Toronto Mketinc, of thk Society. 

A special meeting of the American Society of Agronomy was held 
at Toronto. Canada, on December 29, 1921, in connection with the 
meeting of the American Association for the Advancement of Science. 
The following papers were presented : 

.1. Grain Grown in Combination for Grain Production. C. A. Zavitz, On- 
tario Agricultural College, Guelph. 

2. Method of Obtaining Accuracy in Comparative Tests. R. Summerby, 
Macdonald College, Quebec. 

3. Growing Huham Clover in Iowa. F. S. Wilkins, Iowa State College, 
Ames. Iowa. (Read by P. E. Brown.) 

4 Utilizing the Soil Survey. A. G. McCall, Agricultural Experiment Sta- 
tion, College Park, Md. 

5, Physiological Considerations in Fertilizer Experiments. W. F. Gericke, 
University of California. Berkeley, Cal. 

6. Soil Experiment Fields and their Value. P. E. Brown, Iowa State Col- 
lege, Ames, Iowa. 

7 The Effects of Sudan Grass on the Biological Processes in the Soil. 
Paul KnuTMtn and K. Fletcher, Agricultural Experiment Station, Ames, Iowa. 
(Read by P. E. Brown.) 

8 Eradication of Citrus Canker and Safeguarding the Citrus Industry 

• Recurring Epidemics. EC. F. ECellerman and W. T. Swingle, Bureau 

Of Plant Industry, Washington, I). C. 

g Availability of Floats as Influenced by Incorporation of Barnyard Manure 
Soil I L Lyon and II. ( ). Buckman, Cornell University, Ithaca, N. Y. 
1 ' I Th( I n- ■ '.1 l*Yi tilization mi the Growth of Sugar Beets on Some 
^1 V M MeCool. Agricultural Experiment Station, East 

Lansing, Mich. 

('ONM-.MI N( I. OK XlW k\M .\\l> AGRONOMISTS. 

The eighth annual conference nf ,\Vw Kngland Agronomists was 

held al the Parker House, Boston, Mass., December 9 and 10. The 
following program was presented: 



AGRONOMIC AFFAIRS. 



379 



Friday, December 9, 7:30 p. m. 

Report of annual meeting of the national society, Director S. B. Haskell. 
Report of summer conference o*n teaching of crops, Prof. B. C. Helmick. 
Discussion led by Prof. C. A. Michels. 

Saturday morning, December 10. 

Symposium on seed grading, certification and control : 
Visit to Federal Grain Supervisor's Office, Oliver Bldg., 8 130 a. m. 
Present Status and Needs in New England, Director S. B. Haskell. 
Seed Certification and Control Laws, Prof. M. G. Eastman. 
Potato Certification in Maine, Director W. J. Morse. 
Potato Certification in Vermont, Commissioner E. S. Brigham. 
Discussion led by Prof. G. E. Simmons. 

Saturday afternoon, December 10. 

Symposium on pasture and mowing problems : 

Statement of the Pasture Problem in the Northeastern States, Dean W. L. 
Slate. 

Present Status of Knowledge in Top-Dressing of Mowings. Prof. J. B. 
Abbott. 

Summary of Literature on Top-Dressing Pastures, Prof. H. Dorsey. 
Discussion led by Dean F. W. Taylor'. 
Business meeting. 



INDEX. 



Page 

Acid, Prussic 267 

Acid soils, Toxicity of .' . . 108 

Acidity, soil, Nature of 137 

Adapting fertilizer analysis to crop 353 
Advisory board to National Re- 
search Council, Report of 375 
Agronomic affairs, 

43, 85, 131, 184, 229, 282, 335, 359 
Agronomic meetings, 

85, 133, 134, 135, 232 
Agronomic placement of varieties 337 
Agronomic teaching, Symposium 

on 49, 85 

Agronomy subjects, Prerequisites 

in 49 

Analysis, fertilizer, Adapting to 

crop 353 

Annual meeting of the Society 282 

Minutes of 359 

Approved seed plan 330 

Arny, A. C, and McGinnis, F. W., 
paper on " Methods of ap- 
plying inoculated soil to the 
seed of leguminous crops " 289 
Association of southern agricul- 
tural college workers 134 

Auditing committee, Report of .. 364 
Availability of soil potassium, 
phosphorus, and sulfur, Ef- 
fect of liming on 162 



Page. 



\vn, Percy Edgar, paper on 
" The teaching of soil bac- 
teriology " 

See also Stevenson, W. H. 



323 



Bacteriology, Teaching soil 323 

Beans, Inheritance of disease re- 
sistance in 

Beaumont, A. B., paper on " The 
introductory course in soils." 

' 'I 1m- Soils and Agricul- 
ture of the Southern States," 

Review of 

A. \V., paper on " A com- 
parison of maKtiesian and 
nonmaKnesian limestones" 220 
review 44, 229 



Calcium, Function of, in nutrition 

of seedlings 91 

Call, L. E., paper on " Prerequi- 
sites in agronomy subjects " 49 
Canadian agronomists, Meeting of 135 
Cattle, Effect of hydrocyanic acid 

on 33, 267 

Chemistry of plant life, Review of 

book on 282 

Chicago meeting 85 

Clover seed, red, Home-grown and 

imported 334 

Committee, Auditing 364 

Nominating 364 

Resolutions 367 

Standardization of field ex- 
periments 368 

Teaching agronomy 363 

Terminology 374 

Topographic surveys 3°3 

Conference on crops teaching . . . 288 
Conner, S. D., paper on " Liming 
in its relations to injurious 
inorganic compounds in the 

soil" 113. 

Corn growers' association, Seed 

plan of 330 

15 Cotton, Five-lock bolls in 332 

59 



Blai 



79 



229 



282 



( "ourses in field crops 53 

Cox, J. F., paper on " The Michi- 
gan plan for distributing 
improved crop varieties" 82' 

Cfop production, Relation of fine- 
ness of limestone to 171 

Crop rotation, Value of liming in 206 

Crops, growth response of, Rela- 
tion of fertilizers to 353: 



|80 



INDEX. 



Page I ' I I I / I Page 

Crops, Standardization of courses Gardner, Frank D., paper' on 

m 53 " Liming as related to farm 

Cross-pollination of milo 280 practice" 210 



Damon, S. C. see Hartwell, B. L. 

Disease resistance, Inheritance of, 

in beans 15 

Distribution of approved seed .... 330 

Drainage water, Effect of liming 

on composition of 124 

Dunlavy, Henry, paper on " Fre- 
quency and importance of 
five-lock bolls in cotton " . . 332 

Editor. Report of 376 

Ellett, W. B., and Wolfe, T. K., 
paper on " The relation of 
fertilizers to Hessian fly 
injury and winterkilling in 

wheat " 12 

Experiments, fertilizer, Plan for 304 
Report of committee on stand- 
ardization of 369 

Farm crops teaching, Conference 

on 288 

Papers on 53, 59 

Farm practice, Liming in 210 

Fertilizer experiments, Plan for . . 304 
Fertilizers, Relation of, to Hes- 
sian fly injury 12 

to winterkilling of wheat .... 12 
Fertilizers, Response of plants to 353 

Field crops, Courses in 53, 59 

Field experiments, Report of com- 
mittee on standardization of 369 

Fineness of limestone 171 

First course in field crops 59 

Fly injury, Hessian. Relation of 

fertilizers to 12 

Frear, William, paper on " The 
fineness of lime and lime- 
stone applications as related 
to crop production " 171 

Garber, R. J., paper on " A prelim- 
inary note on the inheritance 
of rust resistance in oats" 41 



Harris, F. S., paper on " Comment 
on T. S. Vaile's discussion 

of Utah results " 316 

Harris' Soil Alkali, Review of . . . 44 
Hartwell, Burt L., paper on " Need 
for lime as indicated by rel- 
ative toxicity of acid soils to 

different crops " 108 

paper on " Relative growth re- 
ponse of crops to each fer- 
tilizer ingredient and the use 
of this response in adapting 
a fertilizer analysis to the 

crop" 353 

and Damon. S. C, paper on 
" Six years' experience in 
improving a light, unproduc- 
tive soil " 37 

Hessian fly injury, Relation of 

fertilizers to 12 

Hybrid oats 259 

Hydrocyanic acid, Effect of, on 

cattle 33, 267 

Improving a light, unproductive 

soil 37 

Inoculated soil, Use of 289 

Inoculating legume seed 289 

Inheritance of disease resistance 

in beans 15 

Inheritance of rust resistance in 

oats 4 1 

Inorganic soil compounds, Rela- 
tion of lime to 113 

International crop improvement 

association 48 

Introductory courses in soils 79 

Johnson grass, Prussic acid in . . . 267 
Journal of agronomy, Back num- 
bers of 131 

Kirkpatrick, Roy T., paper on 
" The approved seed plan of 



INDEX. 



Page 

the Missouri c?rn growers' 
association " 330 



Legumes, Relation of., to liming 

in crop rotation 

Lime. Effect of various forms of, 

on soil nitrogen 

Function of, in nutrition of 

seedlings 

Xeed of crops for 

Limestone, Fineness of 

magnesian and nonmagnesian, 

Comparison of 

Liming, as related to farm prac- 
tice 

Effect of, on availability of 

plant food elements 

Effect of, on composition of 

soil drainage water 

in relation to inorganic soil 

compounds 

Symposium on 

Value of, in rotation 

Lipman, Jacob G., paper on " The 
value of liming in a crop 
rotation with and without 

legumes " 

Lyon, T. L., paper on 11 The effect 
of liming on the composi- 
tion of the drainage water 
of soils " 



206 

185 

9i 
108 
171 

220 

210 

162 i 

124 

113 

89 
206 



206 



124 



McGinnis, F. W., see Amy, A. C 

McRostie, G. P., paper on M Inher- 
itance of disease resistance 
in tin- common bean" 15 

M.k lntirc. YV. H. ( paper on "The 
nature of soil acidity with 
regard to its quantitative 

determination " 137 

Sec a ho Moocrs, C. A. 

MaKiuMan limestones 220 

Meeting*, Agronomic, 

85. 133. 134. 135 232 

Meeting, annual, Minutes of 359 

McmlxrOiip changes, 

H , 131, 1 H.j, 229. 33: 



Page 

Michigan plan for distributing 

crop varieties 

Miller, M. F., paper on " The 

teaching of soils " 71 

Milo, Cross-pollination of 280 

Minutes of the annual meeting . . 359 
Missouri plan for distributing ap- 
proved seed 330 

Mooers, C. A., paper on " The 
agronomic placement of va- 
rieties " (presidential ad- 
dress) 337 

and Maclntire, W. H., paper 
on " The comparative effects 
of various forms of lime on 
the nitrogen content of the 
soil" 185 

National Research Council, Report 

of advisory board to 375 

New England section 133 

Newton, R., paper on " The qual- 
ity of silage produced in 
barrels " 1 

Nitrates, soil, Influence of wheat 

straw on 233 

Nitrogen, soil, Effect of forms of 

lime on 185 

Nomenclature of oats and wheat 318 

Nominating committee, Report of 363 

Nonmagnesian limestones 220 

Xotcs and news, 

46. 86, 131, 230, 285, 335 

N'utrition of seedlings 91 

Oats, Hybrid 259 

Rust resistance in 41 

Varietal nomenclature of .... 318 

Officers for ]<)22 363 

Phosphorus, Effecl <>f liming on 

availability of lf)2 

I'iper, ( '. V., paper on "The sym- 
posium on liming " 89 

Placement of varieties 337 

Plant chemistry, Review of book 

on 282 

I Summer, .1 . K ., paper on " The 



INDEX. 



383 



Page 

effects of liming on the 
availability of soil potas- 
sium, phosphorus, and sul- 
fur" 162! 

Pollination, Cross, of milo 280 

Potassium, Effect of liming on 

availability of 162 

Prerequisites in agronomy sub- 
jects 49 

Prussic acid in sorghums and 

grasses 267 

Quantitative determination of soil 

acidity 137 

Rainwater, Sulfur in 226 : 

Red clover seed. Home-grown and 

imported 334 

Report of advisory board to Na- 
tional Research Council ... 3>.-> 

of editor 376 

of secretary-treasurer 360 

Reports of committee, auditing 364 

Nominating 364 

Resolutions 367 

Standardization of field ex- 
periments 368 

Terminology 374 

Topographic surveys 363 

Resistance, Inheritance of rust, in 

oats 41 

Inheritance of disease, in beans 15 
Resolutions, Report of committee 

on 367 

Rotation, crop, Value of liming in 206 
Rust resistance, Inheritance of, in 

oats 4 1 

Scott, Herschel. paper on " The 
influence of wheat straw on 
the accumulation of nitrates 
in the soil " 233 

Secretary, Report of 360 

Seedlings, Function of lime in nu- 
trition of 9 1 

Sieglinger. John B., paper on 
" Cross-pollination of milo 
in adjoining rows" 280 



'///// P AGE 
Silage produced in barrels, Quality 

of '.l.Vl.Ul 11 if 1 

Slate, William L., Jr., paper on 
" The first college course in 

field crops " 59 

Soil acidity, Nature of 137 

Soil, alkali, Review of book on . . 44 

Soil bacteriology, Teaching 323 

Soil compounds, Relation of lime 

to 113 

Soil drainage water, Effect of lime 

on 124 

Soil. Improving a light unproduc- 
tive * 37 

Soil nitrates, Influence of wheat 

straw on 233 

Soil nitrogen. Effect of lime on .. 185 

Soil, Use of inoculated 289 

Soils, acid, Toxicity of 108 

Soils, Teaching 63, 71, 79 

Sorghum, Prussic acid in 267 

Southern agricultural workers, 

Meeting of 134 

Southern States, Book on soils 

and agriculture of 229 

Spillman, W. J., paper on " A plan 
for the conduct of fertilizer' 

experiments " 304 

Standardization of courses in field 

crops 353 

Standardization of field experi- 
ments " . . . . 369 

Stevenson, W. H., and Brown. P. 
E., paper on " The teaching 
of soils in agricultural col- 
leges " 63 

Stewart, George, paper on " Vari- 
etal nomenclature of oats 

and wheat" 318 

Straw, Influence of, on nitrates . . 233 
Sudan grass, Prussic acid in . . 33, 267 
Sulfur, Effect of liming on avail- 
ability of 162 

in rainwater 226 

Swanson, C. O., paper on " Hydro- 
cyanic acid in Sudan grass 
and its effect on cattle " . . 33 



3«4 



INDEX. 



Page 

Symposium on agronomic teach- 
ing 49, 85 

on liming 89 

Teaching agronomy, Symposium 

on 49, 85 

Teaching. Conference on crops . . 288 

soil bacteriology 323 

soils in agricultural colleges, 

63, 7h 79 
Terminology, Report of committee 

on 374 

Thatcher's Chemistry of Plant 

Life, Review of . . 1 282 

Topographic surveys, Report of 

committee on 363 

Toronto meeting of the Society . . 335 

Toxicity of acid soils 108 

Treasurer, Report of 362 

True, Rodney, H., paper on " The 

function of calcium in the 

nutrition of seedlings " . . . . 91 

Vaile, R. S... paper on " The inter- 
pretation of water-require- 
ment data " 311 

Varietal nomenclature of oats and 

wheat 318 

Varieties, Agronomic placement 

of 337 

improved, Plan for distribut- 
ing 82 

Vinall. If. X., paper on "A study 



Page 

of the literature concern- 
ing poisoning of cattle by 
the prussic acid in sorghum, 
Sudan grass, and Johnson 
grass " 267 

Wakabayashi, S., paper on " A 
study of hybrid oats, Avena 
sterilis X A. orientalis " ... 259 

Water-requirement data 311, 31O 

Water, soil drainage, Effect of 

lime on 124 

Wentz, John B., paper on " The 
standardization of courses in 
field crops " 53 

Western agronomists, Conference 

of 232 

Western Canadian Society of 

Agronomy 135 

Wheat, Hessian fly injury to ... . 12 

Nomenclature of 318 

Winterkilling of 12 

Wheat straw, Influence of, on soil 

nitrates 233 

Wiggans, R. S., paper on " Home- 
grown and imported red 
clover seed " 334 

Wilson, B. D., paper on " Sulfur 
supplied to the soil in rain- 
water " 226 

Winterkilling of wheat, Relation 

of fertilizers to 12 

Wolfe, T. K.. see Ellett, W. B. 



VOLUME 13 NUMBER 9 

JOURNAL 



OF THE 



American Society of Agronomy 



DECEMBER, 1921 



CONTENTS 

The Agronomic Placement of Varieties (Figs. 17-27) ( Presidential Address). C. A, 

Mooers 337 

Relative Growth Response of Crops to Each Fertilizer Ingredient and the Use of 

This Response in Adapting a Fertilizer Analysis to a Crop. Burt L, Hartwell 353 

Agronomic Affairs. 

Minutes of the Annual Meeting, — Report of Committee on Standardization of Field 
Experiments, — Report of Committee on Terminology, — Report of Advisory Board to 
the National Research Council, — Report of Editor, — Notes and News 359 

Ind.x 380 



PUBLISHED BY THE SOCIETY 

41 NORTH QUEEN ST., LANCASTER, PA., 
and 

Washington, D. C. 



Issued January 28, 1922. 



Acceptance for mailing at special rate of postage provided for in section 1103, Act of 
Oita'ajr j 19:7. authorized on June 29, 1918 



JOURNAL 



OF THE 



American Society of Agronomy 

Issued Monthly except in June, July, and August. 



Editor 
C. W. WARBURTON 

Associate Editors 
Crops: CHARLES V. PIPER 
Soils: T. LYTTLETON LYON 

Assistant Editors 

Crop Production, C. A. MOOERS Soil Physics, L. E. CALL 

Crop Breeding, L. H. SMITH Soil Chemistry, W. P. KELLEY 

Crop Chemistry, R. W. THATCHER Soil Biology, J. G. LIPMAN 



MANUSCRIPTS 

Address all correspondence regarding manuscripts for publication, proofs, etc., to 

C. W. Warburton, U. S. Dept. Agr., Washington, D. C. ' 

Suitable articles concerned with instruction, demonstration, experimentation or 
research in agronomy will be accepted for publication. It is understood that articles 
submitted for publication have not appeared previously elsewhere and that they will not 
be offered for simultaneous publication in other journals without the consent of the 
Editor of the Journal of the American Society of Agronomy. 

Papers of any length, between I page and 30 or 40 pages, can be used. Personal 
and institutional items of agronomic interest, suitable for inclusion in " Notes and 

News," are solicited. 

To be accepted for publication, manuscripts should be original typewritten copies 
mot carbons) double^ or triple-spaced, with wide margins. Special care should be 
given to the proper indication of main heads and subheads in the text, to preparation 
and description! of tables, to citations of literature and to illustrations. For fuller 

'Mail* see recommendations on pages 322 to 325 of volume 10 of the Journal and* 

examples in recent issues. 

All illustrations desired should accompany the manuscript, should be numbered 
and described, and referred to in the text. Line drawings must be made in India ink 
and glossy velox prints of photographs are preferred for half-tones. 

REPRINTS 

Fifty reprints of each article will be furnished free. Additional copies will be sup- 
plied at a nominal charge. Covers with printed title page, 50 covers $2.13, and 
rents for each additional copy. Orders for reprints and covers should be «ent to tW 

Editor immediately on receipt of proof of the article. 



AMERICAN SOCIETY OE AGRONOMY 



OFFICERS 



President C. A. MooerS 

First Vice-President S. B. Haskeli 

Second Vice-President C. B. Lipman 

Secretary-Treasurer P. E. Brown 



. COMMITTEES 

EXECUTIVE COMMITTEE 
Composed of the Officers of the Society 

COMMITTEE ON STANDARDIZATION OF FIELD EXPERIMENTS 
A. T. Wtancko, chairman; S. C. Salmon, A. C. Arny, 

COMMITTEE ON TERMINOLOGY 
Charles V. Piper, chairman; Carleton R. Ball, H. L. Shant* 

Consulting Members 
L. C. Corbett, O. F. Cook. 

COMMITTEE ON VARIETAL STANDARDIZATION 

R. A. Oakley, chairman; J. H. Parker, H. K. Hayes, 

E. F. Gaines, H. H. Love, H. S. Hastings, 

George Stewart, J. Allen Clark, A. B. Conner. 



COMMITTEE ON TEACHING COURSES IN AGRONOMY 
L. E. Call, chairman; H. O. Buckman, W. L. Burlison. 



THE AMERICAN SOCIETY OF AGRONOMY 



OBJECT 

Article 11. The object of the Society shall be the increase and dissemination oi 
knowledge concerning soils and crops and the conditions affecting them. 

MEMBERSHIP 

Article IV. Membersl. : p shall be of three kinds, active, associate and local. 
Active membership shall be limited to persons who are engaged in teaching agronomy 
or in scientific investigation in some branch of agronomy. Associate membership shall 
be composed of other persons interested in the object of the Society. Associate mem- 
bers shall be entitled to all the privileges of the Society except that of voting. Local 
members shall have no vote in the Society and shall not be entited to a copy of th« 
printed proceedings without payment of an extra sum of money as provided in Article 
V of this Constitution. 

Active and associate membership may be secured by the endorsement in writing 
of some active member and upon approval by the President and Secretary and pay- 
ment of the annual dues. 

BY-LAWS 

1. The annual dues for each active and associate member shall be $2.50, and for 
each local member $.50, which are due and payable on January 1 of the year for which 
membership is held. 

2. Any member in arrears for dues for more than one year shall thereby forfeit 
membership, but may be restored to membership without action of the Society upon 

the payment of such arrears. 

Applications for membership should be sent to the Secretary-Treasurer, P. E 
Brown, Iowa State College, Ames, Iowa, preferably accompanied by remittance for 
dues, to r.ave correspondence 

PUBLICATIONS 

Proceedings. Four volumes of Proceedings have been issued, as follows: 
Vol. 1, cloth, 238 pp., 39 papers, 1909. Vol. 3, cloth, 286 pp., 14 papers, 191 1. 
Vol. 2, cloth, 154 pp., 16 papers, 1910. Vol. 4, cloth, 160 pp., 20 papers, 191* 

Journal (continuing the Proceedings) : 

Vol, 5, quarterly, paper, 256 pp., 1913. Vol. 7, bimonthly, paper, 320 pp., 1915- 
Vol. 6, bimonthly, paper, 294 pp., 1914. Vol. 8, bimonthly, paper, 400 pp., 1916. 

Vols. 9, 10, 11, 12 and 13, monthly except June, July, and August, paper, 1917-1921. 
Price of Volumes 1 to 9, $2.00; Volumes 10, 11, and 12, $2.50; Vol. 13, $3 00; all 

postpaid. 

Single issues, Vol. 5, 60 cents; Vols. 6 to 8, 35 cents; Vols, g, 10, 11, and 12, 30 
cents; VoL 13, 35 cents. 

Special reduced price to members for volumes 1 to 12, inclusive. 

Libraries and individuals are invited to place subscriptions for the current volume 
and orders for previous volumes with the Secretary-Treasurer, P. E. Brown, 41 North 
Oueen Street, Lancaster, Pa., or Iowa State College, Ames, Iowa.